Go for Chromecast if you're fine with an average solution and are on a budget.
I've tried lots of these boxes, Boxee, Roku, APTV, Chromecast. but each one of them has one little con that turns me off. Wherever it's sound quality, lag during 1080p stream, incompatibility with certain Hdd's. Getting an HTPC is the solution to it all, now I'm wired in with a network cable, get all quality content 720 and 1080 files and actually have setup a simulated cable system (Pseudo TV) for the days I just feel like flippin channels, currently at 50ish channels of HD content.
I actually had Chromecast on my second TV set, scrapped it and built another HTPC. Once you go HTPC and have the means to get the quality content there's no coming back.