as a sniper is it best to defend or attack?...  
obviously if you attack then your getting close to the enemy making your rifle ineffective unless your up high or far back... but then if your far back then you might as well be defending? even though he has higher offence then defence 
thoughts?

I've found that hanging back and destroying their turrets is nice while pushing into their base. The ice trap is nice while closer to their base to contain bots coming out and controlling areas that opponents are trying to come out of.

Pretty much the only sniper 'tactic' I've seen is I'll sit back where nobody can get me and ping shots off at everyone who can't see me :3  But yeah, the sniper's fragile - I wouldn't move forward too much with sniper unless you have a really coordinated team.

I like sitting back and picking off players, bots, and turrets until I get juiced. Once I get juiced I charge into their base and destroy everything. If the moneyball's shields are down, a juiced sniper rifle is by far the most effective way of taking health away from the moneyball.

The sniper is a defensive class. There's no real tactic for the sniper,  they just sit back and pop everyone they see.

Blow up turrets and bots to build your juice up. Once your juice is maxed out, rush in like a mad man. It works for me.