Advantages:

Run these buggers (pun is intended) right to your opponent front line. This will accomplish two things. Fist it will slow down their forward advancement. Second it will break their spirit. When you break the opponent’s spirit you gain the upper hand tactically.

Lets face it, when you start the battle most people formulate a plan of attack. When you charge with the speed the guants offer, you can halt their plan and make then improvise and rethink their whole plan. That is were mistake can happen.

These Bugs are just as deadly in HtH, with mutation you can increase their Initiative to 5, Strength to 4 and Weapon Skill to 4. Making them hit faster and just as hard as Space Marines. Add in Leaping and the Brood size, and you have a swarm that will tear apart any squad. On average you will see about 2/3rds of the brood getting its full attacks. That can be ~ 40 Strength 4 attacks or 60 on a charge. Can you say "Ouch"

Ideal weapons to use against them, any weapon that offers multi shots. These bugs have poor saves, so most weapon will kill them out right. Space Marine should break out the Heavy Bolters and Assault cannons. IG, Ordnance blast will make nice big holes in the swarm.

Then there is the most effective weapon you can employ, Flamers. These weapons make nice Crispy Critters. Just imagine the smell on the battlefield after a brood gets toasted.