I only use pellets if I'm dry hopping or I can't get leaf in the type of hops I'm looking for. Haven't really had any issues beyond a clogged siphon a couple of times.
I'm an equal-opportunity hop slinger. If they're green, smell funky, and sitting in front of me while I'm brewing then I throw them in. It doesn't matter your shape or size - you're going in the brewpot