Depends on the type of suit you have.
It's not bad, but on Impossible It'd be best not to waste too much ammunition on killing them when you can easily avoid a battle.
On Normal it isn't too bad, I only killed them a lot to get some achievements.
But running out of ammo in that game is very bad, unless you got a backup weapon you're screwed. I have a plasma cutter which is almost upgraded completely but I only carry an extra clip or two just in case.
My Pulse Rifle is fully upgraded so I don't need to worry anymore because I can kill them pretty fast now.
