Personally I always go for disintegration. Less danger of hitting yourself. Great against spiders. Super fun to hit enemies from across the map and through walls.
Hard to say, not knowing anything else about your equipment load out, or what other wands you have.
For my play style, I generally prefer the Wand of Disintegration because it's more versatile. It scales with each enemy struck in a single shot, and gets more powerful through walls. I like to kite mobs into corridors so they're lined up, and soften them up before a melee attack. Mind vision is also fun, and lets you snipe at mobs from a room or two away.
Corrosion is also good for softening up mobs at range, but is less effective on fast mobs at lower powers. You also need a lot of room or an escape route to use it, whereas Disintegration has no area effect on the player.
Neat, you got a want of Corruption early. Its +0, which is a bummer, but it could make for a necromancer run.
If you have the wand of Corruption and get the Embers quest then you can imbue your staff with Corruption and upgrade it to like +6. As long as you have the embers, wraiths will spawn that you can turn into allies, or at at least friendlies.
Then you can put talent points into swapping positions with them son you can blink back and forth with their position. I think also mind vision effects plays well here too, as long as you're within range to blink.
It's a niche style, and the wraiths' spawn rate is challenging to keep up with. You'd want a ring of energy and/or a chalice to keep up. You'd also want utility wands like MagicMissile, Frost, PrismaticLight or Earth to put down any rogue wraiths you can't turn in one shot.
M OKs like you already went with disintegration though. Good choice.
Go for corrosive almost ever. It's op if you know how to use it. I'd imbue it with your mage staff. The more max charges your corrosive wand can have, the better, and the staff gives you one more max charge on the wand you imbue. It deals so much damage and, as it is AOE, you can take multiple enemies at once. Takes some skill over how the gas expands (it expands differently in tunnels) and on when to use it, but if you know how, it is absolutely powerful and arguably the best staff (or the second best) in the game.
i have used corrosion in past and yeah it's great and i know what you are talking but i won't call it the best or second best, there are better wands, also i would like to keep the staff imbued with magic missile as it gives upgrades to my other wands as well which is pretty damn useful