I invested my first CE purchases into the gunslinger line, but have since switched to bombs because, although fun, I found the fact that my teammates would slaughter most of the monsters with swords and bombs before I could even injure one with a gun incredibly frustrating.
Of those I've tried:
Gun: Hail Driver
Summary: Slow, low chance of freezing, bad ricochets
Detailed: The alchemer lines are all a bit slow for my taste... I feel like I could throw the bullets faster than they currently move. Anyway, the freezing mechanic and ricochet mechanic could both use some improvement. Unlike shock or fire, for example, the cold alchemers can remove the status effect they just inflicted. Why? The way things are, not only do I have to fire one bullet and then wait for the reload, but I actually have to wait to see if the bullet froze the monster so I avoid shooting it again. This renders it pretty useless, as the gun is super slow anyway and waiting while running away makes for a bad combo. Ricochets can also break the freeze, but they also usually seem to bounce directly back at me. Since I'm usually running away from enemies this renders the ricochet effect useless. What if they could bounce in any angle from the block/monster they hit?
Gun: Silversix
Summary: Split damage = bad, large clip = good, auto-dodging enemies = really?
Detailed: Can we have at least one enemy that this gun is extra-effective against? The split damage really hurts this line. The large clip makes this gun one of the few I liked to have in arenas or danger areas or, really, anywhere, even when another gun was more effective against the monsters I was fighting. Still, with dodging enemies I can't use any guns at all, let alone this very-fast gun, because not only can the guns not hit them, but they dodge out of range of my group-members. With the 6-shot clip no one can hit anything.
Gun: Magnus
Summary: Hate...standing....still. Especially for 2 shots.
Detailed: I expect to be able to run and shoot. It's not like it does the damage of a rocket launcher.
Gun: Pepperbox
Summary: Short range.... why not just use a sword?
Detailed: This gun isn't as bad as I made the summary seem. I thought I could do a graviton/pepperbox combo to suck the baddies up and light them on fire, but it didn't work as well as I hoped. :( When I charge the gun I need to be so close that I may as well use the much more damaging charge attacks from a sword. Actually, I haven't found a single charge that I find useful on a gun.... Ah well. Other than the range I actually like this gun.
Good luck with the balancing. I'd love to go back to using guns....
I think right now we all can agree that no gun stacks up to a sword or bomb in damage or crowd control. We've made our points on those, so until something is done that we can be satisfied with, there's no way we can honestly compare guns to any other weapon. Right now we need to be focused on imbalances gun-gun. If they do make a change, it'll be a broad overall change, and only those between each gun should remain.
Keep in mind, there's a difference between imbalances and the qualities of the gun. As heavy weapons, it makes sense for the Magnus and Autogun lines to stop us from moving, but if their damage or capability doesn't stack up against the other guns, then changes need to be made.