My only complaints are that I wish the game were longer and had more missions to flesh out the characters!
I got the game on sale for about 30 dollars with another Batman game and would not pay original price for the length.
On another note, I so looked forwards to coming back to the tower and looking for their character icons to see if I could progress their individual stories but they were just so short and didn't quite feel in depth enough to make me feel engrossed in their development. As people outside of the masks.
Oh my gosh the characters are so nice to play though! I love the fighting system and how smooth specifically nightwing plays (I have a clear favourite character). The mechanics are great and the way they're integrated feels very natural and easy. By the time fast travel was introduced, I felt like I knew the world enough where it was rewarding. I also appreciated that the map wasn't overwhelming like a lot of games are these days. There is enough on the map to feel interesting but never too much so I feel unable to do it all.
All in all, buy it on sale and you'll enjoy it hopefully!