I've had a Fire Stick since Christmas and it's been great. What are the knocks on it?
FireTV (not stick) is the way to go between those two. Fire Stick doesn't have a very strong wifi connection
I've never had a Wifi problem with my Fire Stick...
I will say that I have both, and my summer house has spotty wifi. I can stream much more consistently with the FireTV than my FireTV Stick. In normal applications, I'm sure it will be fine.
One cool thing about the fire stick (not sure about Roku), is that you can jailbreak it and install third party android stuff on it like Kodi. I am not a programmer by any means and I just followed a step by step guide that I googled and figured it out.