Sniper, because they're often much less likely to contribute to winning. A bad Spy at least makes a person turn around for two seconds, were as a bad Sniper won't make anyone do anything different. --- My balls do not blend.
Even the best Spies are rendered useless with good spychecking and an aware team. Good Snipers will kill you the second your head pops out of cover --- http://i284.photobucket.com/albums/ll2/jkjklkl/Cool/f6b07f5beda303d7.gif
I dont hate either of them... but spies annoy me more. Those rare times when you find a godly sniper its impressive. All a spy has to do to be annoying is DR while your team either wastes time focusing waiting for their invuln to run out or ignores it and pays the price.
Spies, you can look for them. You can shut them down entirely if you're competent, no matter how good they are. Snipers? You already know he's there. But there's nothing you can do about it. If he's terrible, you're in luck, as that's one less enemy to worry about. If he's good? You can't even walk around a corner without dropping dead anymore.
I vote for Sniper. --- Official Lopunny of the Black 2 Boar . . . wait, how did THAT happen?!?
if you would have asked me three years ago, i would have said spy simply because its a fairly unique mechanic in an fps game.
however, most spies, i have come to notice, suck. easy to spot, they tend to only get me when the action is too hectic for me to watch my back. snipers however.... sometimes there's absolutely nothing you can do except hope that jumping around and crouching randomly throws off their aim. --- "bomb the living bejeezus outta those horses. that's not enough." "brought to you by medicine prescriptions and dead again christians."