@TrenchLord, I can only share my own experience.
I took a long break from video games, and after 8 years I got back into them and in February I got MK9 for my PC, hoping to learn the story and then pick up MKXL.
Unfortunately, after a few weeks, I kind of didn't like the feel of MK9 and was looking for something a little different and settled on SFV.
What I didn't like of MK9 was the emphasis on juggle combos and unrealistic physics. I'm also not a fan of the sort of dial-a-combos found in MK9. I also wanted something that allowed for cross-ups (holding back to block).
I know Injustice would have been good for cross-ups, but not the other things so I started looking around.
SFV still has some juggle combos, but the emphasis is far less, and the jugglee doesn't bounce around as much.
There are some dial-a-combos (called target combos in SFV) but most of the combos in SFV are based more around frame data and cancels, so there's more variety in timing. Consequently, hit-confirming is a little harder because you have to react almost right away, but at the same time, you hit-confirm off of one attack, instead of just jumping right into a combo that the opponent blocks and punishes you for.
I also found that attacks seem to have more weight to them (as in it really seems like you can sense the power behind the attacks), whether it hits an open or blocking opponent, and this tiny little thing really seems to make the fights seem more enjoyable and get me more interested in the fight.
People do have some complaints about some of the mechanics. I'm not a fan that getting hit while you're in the early stages of a back dash will lead to a Crush Counter (a counter that does more damage and leaves you in a longer hit stun, giving the counterer more time to hit-confirm and punish you)... But then again, this mechanic prevents you from rushing in, attacking, and then dashing out. It sort of makes you commit to the rush-in.
SFV is a pretty fast-paced and offensive game. There seems to be more offensive options than defensive options. Some people like to rush in, and others like to stay back and counter. I think a lot of people's complaints about the mechanics are the latter type. I like to rush down, so SFV is great for me. It does seem to reward the more aggressive player.
Also, the net-code for I2 and T7 does seem to be better than SFV. With that said, I have some internet issues and only have played MK9 and SFV offline.
For what it's worth, I played MK9 for about two to three weeks before I got bored and bought SFV. I played SFV everyday for over two months before trying GG Rev 2, but after about a week of GG, I went back to SFV and have been playing that everyday for the last two weeks, and I don't think I'll play GG anytime soon. I also uninstalled MK9.