I dug it. I had never seen the prior seasons so I just caught those 3 on Netflix/Amazon recently so I don't have that deep engraved "cult following" mentality a lot of the fans do.
I thought it was solid. It's definitely different than the prior seasons, but I really dug how it started at the same place (end of S3) and ended for each character in the same place.
Instead of just saying "5yrs have passed and X is now Y and Z is now B, etc" they actually dedicated the season to properly catching you up with each character.
Also I know that since this wasn't a full series type thing so all the actors came back and did this for the love of the series, and creator, and did as much as they could in between filming their other projects and work. So I know that affected some of the character time.
All in all it was good. Now we're caught up so if S5 get's green lit that will be the "make it break it" season for me since everyone is back on the same point in the story, and we have seen everyones back stories for the missing time between S3/S4.