Home made Media Player/streamer vs Roku etc

[Disphotic]

Hi! I'm going to get myself a media player/streamer for my TV.I don't pay for channels as I see no point when I can just get Netflix/Hulu+ etc and pay 1/100 the price and watch every show I want.

Now, there are different "Media players" on the market like:

Roku
Xtreamer
Apple TV
etc etc

Now, these got built in "operating system" or whatever I should call it, like, they could decide to take Netflix off if they wanted to.

So I thought, why not build my own by just buying a small cabinet like this: http://images.anandtech.com/doci/611...of%2010%29.jpg and install some free operating system like Linux Ubuntu, and then I could install software that lets me watch Netflix and get access to every content (Media Hint firefox addon), so it would be an "open source" media player.

Is there any downside with doing this that I have missed? Will the image quality be better on my TV by using for example Roku instead of a home made using Linux Ubuntu?