I got a few games a couple weeks ago (Mafia 2 for 7 bucks!), and I like it.
Download speed was fast (1meg/s, about as fast as my service can go), installation is pretty straightforward, it keeps a list of everything you've bought and lets you redownload them as many times as you please.. Amazon says each key they give you for a purchase only has X amount of uses, however when yours are used up they'll "Happily provide you with another, at no additional charge".
Doesn't specify any DRM, so I'd guess just whatever the publishers includes with it will be on the product page.
Hope this helps.
edit:
Also I guess since they have to compete with Amazon's boxed prices, pretty much everything I see is cheaper than Steam.