A lot of people say the suit is a gimmick, but it really isn't, and takes some time to actually figure out how to use effectively. In the multiplayer open beta, it was pretty important to know when and how to quickly change between modes. Though it had it's problems. Stealth mode wasn't really stealth, as it would still cast a feint shadow on the ground, or if you looked at someone invisible properly you could see a feint shimmer, which is a neat effect, but sometimes made it a bit useless. It's definitely useful for long range sniping though, fire off a round and cloak before someone spots you.
The power armour is killer though, as one punch kills everyone. So if you find yourself low on ammo, or with a bad weapon, you just sprint up to someone and punch them in the face. Also the super jump allows you to quickly get into good positions for kill people from above.
All in all I found the multiplayer to be pretty fun, and I don't really play a lot of multiplayer anymore.