What I loved
The new thumbs themselves. They look great! What I like most with the new thumbs, is what they've done with the larger deviations. It's safe to say that I won't miss those skinny, hard-to-click thumbnails (which are usually in the Tutorials gallery or deviantART Suggestions).
Left-alignment. Unlike most of the community, I actually like the left-alignment. I guess it's just a preference. It just looks better to me.
Literature Thumbs. These are probably my most favourite thing about the new thumbnails. They look more professional and I'm digging the lighter look! Now I know almost nothing about literature, but I'm sure the literature community will love these new thumbnails.

What I didn't like
Whitespace. It seems to be the new thing with social networks lately, with Google+ recently updating and having A LOT of whitespace. deviantART's whitespace isn't that bad. But with some of the space, it could easily be filled in with another deviation. Exhibit A:
Now if this space was filled in, it would be perfect. It just looks like something's missing, and if someone visited deviantART for the first time, I think they would think the same thing. Some order needs to take place!
The gallery/comments subtitles. I love them, but something seems a little off. I feel like there shouldn't be that much of a space in between the title and subtitles.

Conclusion
I'm mostly happy about the new thumbnails, it's taking deviantART in the right direction. There is a few things that need to be improved on. If anything, the whitespace is the thing I'd like to see worked on the most. Thank you to the deviantART Staff for running a site that all of us enjoy.








As much as I don't mind the background on the thumbs, I don't see the point of them.
I also really like the large deviation thumbnails!
Great review, btw.
When you said "thumbs" I thought you meant embedded thumbnails like in journals and stuff
No, they don't look so bad at all.