FIFA is really good, but NHL is right there if not just a step below. Since 09 it's been a pretty great game of hockey, though I stay away from the EASHL because people just exploit there.
I like playing a challenging CPU and 14 has that and is more fun than 13 to boot.
FIFA and NHL are probably the two games/series I've played most. I guess it depends what game mode you spend most of your playing time in when judging the game. I play GM mode in both unless I'm playing with a friend, and I can say without hesitation FIFA is WAAAAAAAAAAAAAAY better than NHL when it comes to GM modes. Well, I prefer NHL because I'm a hockey nut, but FIFA is just a better quality product.
I didn't buy NHL 14 (maybe they changed this?) but in NHL if you are looking for players with a specific skillset you can only search out players by going through each team, then sorting through the names, and then either scrolling way over or selecting the player's full profile screen to see stats. It's an enormous pain in the ass. In FIFA, you can simply enter your search parameters and it shows you every player that matches your criteria regardless of team. If NHL applied FIFA's method for searching (which really shouldn't be difficult to do) I could easily find fighters that can actually play, or prospect D that are huge, rate well in hitting, AND can skate. This is extremely difficult in NHL games. I know most current players, but when you factor in often wonky player stats, or you are several years into GM mode and it's a bunch of randomly generated prospect names filling out rosters it becomes ridiculously tedious trying to find what you are looking to acquire.
I also have had bugs in NHL, but never FIFA. I had a GM mode I'd been working on for like 9 months basically ruined by a bug. Several years into a GM mode if I loaded a saved game after the prospect pool for the draft was generated (i.e. if I didn't spend an entire day playing non-stop to finish the season in one go lol), ALL the prospects sucked after being drafted. Like, not one player with more than 2.5 star potential. After multiple seasons in a row where this happened I tested simming the whole season in a continuous session, saving but not loading after the prospect pool was generated. The top prospects had a few high end guys, as should be expected. Loading the save (same names/prospect pool that ended up with multiple high potential guys before) and simming to the draft, all players had 2.5 star potential or less again. Basically broke the game for me since no quality players could be drafted to replace declining players anymore unless I decided to waste a season by simming every game to get through it in one session. Never had bugs playing in FIFA... And of course the in game AI is far better in FIFA.