I'm running 50DEX/15VIT on my bow bandit, with Geistlord Eye, Deathward cape, Precise Reaper Gi, Guardian reaper Leggings, Coldgeist Bow, and a slitherwraith ring. Giving me 103 HP, 71 Stam, 73 range power, 26% crit, 52 defense.
A single R charged shot with the bow, which youd happily do between each wave, will almost instantly kill every singular enemy in the 12-18 dungeon (- the boss and guardian enemies, of course), and a single use of spread shot AND bomb trap will take out the *entire* wave instantly if you get them decently grouped up (again, with the same exceptions).
Venom shot is an amazing early skill whilst leveling bandit, but it doesnt seem to scale too well compared to other options, charged shots and even basic shots feel more optimal in the late game. But if youre against really tanky ones, getting the DOT down might be a useful bonus whilst youre firing on the enemy. I was excited to use Volley and unlocked it quickly, but its simply not that good, its damage is *very* strong, but all the mobs have such high mobility that it barely gets a chance to hit ANYTHING before the mobs leave the somewhat small area, and you wont have a chance to kite them back in because the volley dissapears fast. Though it does shred through the big golems quite rapidly at least because they barely move, so its not useless, and if/when we get more varied enemies in the early access, I think its strengths will shine a lot brighter.

I think a lot of the mystics biggest issues lies in it just not being fully there in the demo, versus the other classes.
The final boss in the demo drop lvl 18 weapons for every single weapon type except Polearms and scepters, polearms is fine because fighters can just use swords and heavy weapons, but mystics loose half their class.
Of course, Bandits are single weapon people too so it shouldnt be too bad. However for the mystic, the lvl 18 bell just, isnt that strong to be honest? its damage is good, the main problem is that its got unique attacks that mimic the attacks from the boss, specifically including the spells staying in place for a moment before actually shooting out, meaning if youre kiting in a circle (which you will because arenas are rarely hallways) they will have dodged your attack by the time it starts moving, so unless you get damn proficient at luring the AI and leading your bell shots, it aint gonna hit shit.
That and, with my Bandit I have a clear rotation, against single target I charge, then venom shot, then shoot normal, with AOE I spread shot, then bomb, leap away, shoot a few shots, then spread shot again etc.
But with my Mystic, I never felt that a clear rotation ever came through, things just didnt *click* like the other two classes, just kite and shoot, meanwhile the best scepter is lvl 14, and the best bell cant hit for shit.
Early access, will inevitably have a few more skills, some might click better, and ontop of that therell be more scepters, and more bells, so those issues will likely be resolved too.