I've been in the beta for a while now. Wanted to like it, but I just can't seem to get into dota2 at all. Probably 200ish games of DOTA2 played now. I've got about 2k games played on LoL, been playing that since beta as well. LoL is basically my favourite online game so I may be a bit biased. Spent some time with HoN, but stuck with LoL since it was free and haven't looked back.
I just hate the UI in dota2. There's a huge lack of information present on-screen compared to LoL. It's all there, but you have to mouse over everything and wait for it to pop-up. I found that incredibly annoying, I'd rather be using my mouse for useful stuff than wasting time mousing over icons that could simply show numbers. The store is also atrocious, the organization is basically non-existent. That really doesn't matter anymore, now that I know items and builds, but at first it was aggravating. In LoL there's clear categories for each item type; defence, offence, mana, ap, ad ect.
And the UI itself is massive in-game. Like 2/3s of your screen is basically the ugly grey UI, and 1/3 in the centre is the game.
I don't find either game "better" than the other gameplay-wise. Personally I just find dota2's UI to be so horrid it makes the game less enjoyable. Not that LoL's is perfect, it's got issues too. But none as glaring and obtuse as dota2.