I've been using Liferea on linux but it doesn't support atom feeds it seems. I like it because I can turn off scripting for web pages it loads, I really just want a list of headlines and to open things in another program. So I could do with something a lil better.
I use NetNewsWire on iOS and Newsflash on Linux, and sync them together with a small FreshRSS server. It's a bit of a mess, but it's worked well enough for me.
If you have a Mac and iOS device, you can use NetNewsWire on both and sync them with iCloud.

