Final Fantasy XIV Might Be My First MMO Experience

I have never experienced an actual MMO before and I plan on starting with the newest entry in the Final Fantasy universe. I understand people still play stuff like WOW and FFXI but I want to try and catch on with the “new thing.” I have some concerns about it though that I need some advice on.

For starters, the time factor comes to play. I game a ton of different games across almost all genres. I also might play 5-10 hours in one week and maybe 10-25 hours of games the next. I’m not entirely sure how much I’ll be able to play this game which comes to question is it enough to enjoy this game? What if I only play it for like five hours one week. Subscription aside,
is that enough to enjoy the game or would I be wasting my time?

Another factor is if this will be too hardcore for me? I know my way around a RPG and I’m a big Final Fantasy fan; but I hear FFXI takes quite a while before it becomes enjoyable (I eventually gave up on Final Fantasy XIII because it’s linearity was bothersome to me.) I guess the question is should I start with something more simple or should I not worry about it?

My last question is one that might start some flame. I really want to play this on PS3. I know the game is coming out first on PC and will probably be way better on it but I’m not sure how my PC would handle it which is why I would rather play it from the comfort of my couch with my PS controller. Will it hamper my first experience that much or should I save up to upgrade my PC to run it?

If their are any free MMO games I could play also please recommend them to me. Thanks everyone for the help.