Gog by far.

Haven't tried Amazon's service.

Steam and Origin are drm clients. Origin is bluntly obvious about that.

Steam and Valve as a whole are the group responsible for kicking off this whole online client based drm mess so I have the least fondness or patience for. All the laziness inducing auto-patching and modding portal for the even more lazy isn't going to change my opinion. When Valve start to release drm free then I'll be interested. As it stands they're simply saying - customers can't be trusted and need to be treated as though they are by default pirates. The opposite of gog.

Not sure how widely people know of this one but thought it might be of interest. Nearing its total but the expansion plans if they go over the total look to be interesting.

http://www.kickstarter.com/projects/1535515364/knock-knock

If you've tried any of Ice-Pick Lodge's work you'll understand they have a reputation for an almost carefree anything goes attitude - a willingness to experiment in their approach to making games. You might have tried the brutal Pathologic or the unnerving The Void or the lesser known but bizarre Cargo!

They seem to be looking to become a more independent studio and work directly with the players now which is interesting to see. Knock Knock is the first project that they've put up on Kickstarter.

Any players of previous Ice-Pick Lodge titles around? :) Any other Kickstarters you'd like to share or raise awareness of?