Just beaten this, thoughts below:
+Excellent game length, took me about 109hrs and still got a bunch of other quests to go
+Good looking game IMO, some great vistas, water and foliage generally looks good etc
+Absolutely loads of NPCs, also quite nice seeing them get involved in fights with dragons etc
+Decent performance 72-144fps
+Good variety of quests, overall I would say more enjoyable than Oblivion
+Although I focused on a dual-wielding melee character, there were a few occasions I used a bow or magic and it felt like they were viable options. This made for varied combat and provided another option for tough fights (sitting back to deal some damage before engaging in close-quarters combat)
+General good feel to the environment, lore etc - makes it feel like an RPG in the truest sense rather than just a formulaic game
-Suffers from the same inventory management issues as all the modern Bethesda RPGs, I would estimate at least 20% of my play time was spent shuffling items around to ensure I was bring back the most valuable loot (this game could really do with a value:weight ratio sort)
-Final boss seemed pretty easy compared to some other monsters like Ash Spawn. Second half of the main quest line I was able to push through very quickly, kinda annoying to discover the shout that pulls dragons down to ground level over 100hrs in.
-Dialog interface is a bit clunky, annoying that you have to do multiple clicks to enter trading with an NPC, and the cursor selection doesn't always work properly (selecting 'MISC' during trades with vendors is particularly annoying)
-Alchemy / Smithing balance is a bit off, you very quickly seem to go from having basic skills to be easily crafting £500+ potions from common ingredients or making/upgrading armours etc, whereas I would have expected a more gradual transition. This has a snowball effect because it also drove much more rapid levelling for more, I reckon 25-50 took about half the time that 1-25 did.
-Couple of annoying glitches where a quest wouldn't complete or similar
-Follower pathfinding is terrible, in most dungeons my follower gets left behind at some random point so I have to find a transition door to get them to re-appear (unless they got killed, in which case I have to try and figure out where so I can loot the corpse)
-Some of the Dwearner locations dragged on a bit, there was one in particular I got fed up with because I needed to sell/store some loot but had been trekking for miles through this dungeon
Although I think it is an excellent game, I doubt I will invest much more time in it, as having maxed out a few skills it is starting to get quite repetitive.