Galbadian soldiers tend to be the physicaly weakest of the organized miltary forces in the world, because they rely almost exclusively on guns and machines. In general, a Galbadian is a poorer soldier than any other reconized national force, at least individualy. However, the Galbadian army is extremely large, and very well orgainzed. Galbadian solders pull off group manuvers well, and their officers are well schooled in tactics that help them overwhelm better equipped and trained forces. Ten Thousand Galbadian soldiers is a serious problem. Multi-tens of thousands of them is a nightmare.
It is essentialy only because of Galbadia's hunger for the land grab in Centra that some of the Leauge of Roses fiefdoms have not fallen to Galbadia again, were they to exert their full military might on the Leauge, it could not help but lose at least one member.
Galbadians use guns, as stated above, but they also employ a wide variety of mecha in support of their troops. These robots take on the brunt of bigger monsters and especialy powerful foes like SeeD troops, freeing the infantry to fire without worrying about physical combat. Galbadian troops also have a cavalry division of motorcycle troops which tend to be much more highly trained. They have a paratrooper division as well, who's soldiers are trained both in parachuting from aircraft and using "jump harnesses".
Galbadian mecha tend to incorporate some rudimentary magic, through the use of techniques that lag far behind those of Esthar, but follow the same basic ideas. Some officers, especialy commandos, are outfitted with special devices that allow them to cast a spell or two as well. Such officers tend to be far more physicaly capable than the average Galbadian soldier as well.
Finally, Galbadian military security is among the top in the world, their bases and prisons are more secure than probably those of any other nation or military force. In the case of SeeD, the extreme power level of it's members negates the need for any sort of intense security. The other nations simply don't have as well developed techniques for keeping places secure as the Galbadians do. In fact, the only real hole in Galbadian security is that the sheer size of their forces makes knowing everyone impossible, and thus disguises are some of the best ways to break in. Still, this is obviously an extremely risky route to take, since if the disguise fails, there's no real way to hide or flee. It's often as hard to get out of a Galbadian base as it is to get into one, if the door is closed.
Esthar Soldiers come in two types, regular humans, and cyborgs. The human soldiers are trained to a much higher level than Galbadian soldiers are, they are usualy competant in melee combat as well as with their guns. In fact, the standard Esthar weapon is a shotgun or assault rifle with a blade descending from the bottom of the weapon. The Cyborg soldiers are even more dangerous, they're augmented beyond normal human levels, and are fitted with devices that allow them to cast spells as effectively as a SeeD who's junctioned a GF, though they tend to have a much more limited selection to chose from. Worst of all, Cyborg soldiers are almost always augmented to the point that they are able to perform limit breaks.
Like Galbadians, Esthar soldiers are supported in combat by various robots and machines, though Esthar support mecha tend to be highly magitechnical, rather than a robot with a bit of magitech thrown in on the side. Many of them can hover, and all of them can toss magical power about with abandon. The only thing more dangerous than a squad of Esthar cyborgs and mecha is an equivilant number of SeeDs, they are not to be taking lightly. Esthar definently prusues quality over quantity, both because they have a smaller population than many other nations, and because they have the technology to put their soldiers above anyone who hasn't junctioned a GF or two.
Esthar troops work best in small units, they are essentialy all special forces, like SeeD troops, and their tactics tend to be similarly designed for the small groups. Esthar military bases are usualy highly magitechnical, and while it might not be impossible to get in, they are very good at sealing off important areas with force fields. In addition, the technology is often too confusing for would-be infiltrators to operate properly, many times an Esthar base will descend into the ground like an ant hive, and utilizing the many transport tubes and elevators is the only way to effectively get around.
The Centra Conferderacy is a very new government, having formed in the past five years from all the disperate tribes and city states that once dotted the isolated continent. Accordingly, their military is not enormously organized yet. Centran Soldiers tend to come from the ranks of militia and monster hunters, each soldier is probably better trained than even an Esthar soldier, but lacking in any magical augmentation. Further, they have a lot of people but are unable to work in large groups effectively, so they tend toward medium sized formations instead.
There is no "standard" weaponry among Centran soldiers, instead each person uses whatever weapons they were accustomed to use when fighting monsters. Melee weapons are almost universal, and this has in fact been their only advantage against Galbadian troops. Provided they can close the distance before being cut apart, Centran troops are devestating against the Galbadians, who lack in melee skills. The times they have been unable to close with the Galbadians have been pure slaughter however.
Centran troops have no real support backup, other than calvery units on light vehicles, and a reletively small number of armored fighting vehicles, from tanks to armored troop transports. They are feirce fighters however, and rarely if ever have a failure of morale. Once Central soldiers have engaged, you can be sure that they are there to fight. All in all, they can hold their own against Galbadians with some luck, can even dominate Leauge of Roses troops, but against Esthar troops or SeeDs, they have little or no chance. Luckily for the Centrans, they quite often hire SeeD to bring them up to snuff in areas they lack, and thus haven't had many engagements against the world's foremost soldiers.
The 'soldiers' of the Leauge of Roses are the vast majority of them simply peasants who were handed a gun. Over 90% of the Leauge troops are cannon fodder, and thus, they aren't the most effective army the world has ever seen. That other ten percent tend to be highly trained Samurai and warrior Monks however, and they can be extrodinarily dangerous on the battlefield, especialy when supported by large number of peasants firing away with automatic weapons. The Leauge has money, at least so far, and it's soldiers remain well equipped. If they eventualy decided to train these peasants is another matter, so far the standing army of the Leauge has been around for barely three years.
The general consensus is that unless the Leauge trains its peasant troops, they will be doomed a second time when Galbadia gets around to crushing them. There simply aren't enough Samurai to handle the modern and focused group tactics of the Galbadians, and people like General Caraway are no slouches at stratagy. Support vehicles are nearly non-existant in the Leauge, other than transports, though there are some reports that the Leauge is trying to create airforce and armor units to cover this deficiency.
There are other informal militaries that exist, mostly among the Bedu tribes of eastern Centra, or pirates and bandits that have managed to persist long enough to have something of a history. In general, they fall like wheat before a scythe to any of the above forces, or SeeD. However, they can occasionaly be dangerous, and especialy the Bedu are said to have learned some things from the 'djinn' of the desert. The official SeeD doctrine is to hit these forces hard enough that there is no time for them to bring up nasty surprises. In any case, General Lionheart is extremely discouraging of playing with one's foe, as he finds such games distasteful and dishonorable.