Should I Z97 or H97?



I was thinking of (later) upgrading to an i7 or adding another graphics card in?
 
No problem.
I cannot comment on that. On the face of it, a chipset that is built for overclocking would be more stable than one that is not.
Perhaps those folks have just had a bad experience with a specific motherboard model or unit.
ASRock is known for building decent well priced hardware, so you should be good.