So I've got 3 characters now. A paladin-type (one-handed, heavy armor, restoration, alteration, block), a mage, and a thief/assassin. First two are about mid 20s and the assassin is about 30 now (he's going to be my main). Super fun. I've done all of the mage, warrior, and dark brotherhood quests on one character or another. Done part of Imperial/Stormcloak on a few but haven't finished either. Still need to do thieves guild. I'm only like 4 quests into the main quest. I'm starting that more tonight. All of the guild quests (or whatever) are super fun and engaging. I've loved all of them so far.
You start getting crazy shit at about level 30. I can make like 10k gold from clearing out a dungeon. It really makes me HATE the buy/sell vendor system, though. I'm so tired of having to port to 5-6+ places just to find enough sellers to buy my crap. Is there a mod that fixes this? Either gives the sellers way more gold or does something else to make it not so annoying? If not, I may just start dropping all of the stuff I found in a dungeon and giving myself 10k gold via the console. I feel like I spend as much time exploring as I do selling, and I have minimal use for money anyway.
Assassin guy is pretty fun. With the right perks and the right gear, I can 1 shot anyone if I sneak attack. I haven't found anyone that can withstand it yet. Dragons are a pain in the ass for a stealth character though. I just run. Unfortunately, quests with other NPCs can get borked because they break your stealth (IE a quest where you and some guy have to go and clear a place out). There's no option to make them wait so they just waltz into a brightly lit room following me and alert everyone. Then I usually can't get sneak attacks. Haven't found a way to stop this yet. If anything, I find this character to be a bit too easy. When you hit 100 sneak + armor bonuses, it's literally almost impossible to be detected if you are crouched.
Mage is really fun too. Might be my favorite. My norm is to cast an alteration shield, conjure an atronarch, then spam destruction spells for whatever that atronarch is (IE if Frost, use frost spells). Heal as necessary. Dual casting is awesome. Mage gear is great, too. and there is plenty to go around finally. Overall, I like mages a lot more in this ES game than I ever have before. I'm so happy with how far they have come from Morrowind where Magicka never regenerated.
My pally is really strong, but the gameplay got a little too mindless for me. I would cast an alteration shield, then just charge into battle with my 1 hand and wail on whatever I was fighting. I'd use a strong heal whenever I needed it. Even with generous health upgrades, I can heal 75-100% of my health in one heal spell, which takes at most 1 second to cast. The result is that I am seriously invincible so long as I am not facing 10+ guys. Most things die pretty quickly with my sword. Hack slash repeat snoooze.
I haven't done any smithing/enchanting yet. I'll need to work on that.
/random impressions and thoughts