I played sniper for all of about 5 minutes, purely and only to unlock his things. The fact that you have to pause for a second when you reload seems kind of killer. With skill, I guess you could reload very quickly (first pass of the bar) and so while jumping so you don't stop moving while reloading. His aim ability is nice, though, given it pierces.
You could try huntress, who can shoot while moving and automatically targets whatever is closest (so you can run away and shoot behind you for example); however, she felt a little wonky because her glaive and bomb shot don't always autoaim the same way as the main attack. Her lack of infinite-target (read: piercing) attacks can make clearing packs annoying, but that is true for several classes.
You could also try the miner. You cannot be hit while dashing, so in my opinion he offers quite a bit more survivability than most classes. It's like having the commando's roll twice, and you even do damage while using them. His other ability is also nice for jumping and blasting the large packs that accumulate at teleporter time. But you have to learn not to use his main attack all the time as you would with some of the others. (Back in the demo I had way better success with the miner than the commando, even though most people preferred the commando.)
Of course, you have to unlock these so maybe this isn't useful.
Though in all, it feels mostly like luck plays a big factor (in terms of good early drops). If I survive to the temple it's usually because the drops I've collected are such that I can just steamroll everything. But I think the same of things like DCSS (although the random factor there is in things like monsters taking double turns), where truly skilled players can win even when they hamper themselves, so luck just covers my lack of skill.