I stuck with Madden 05 myself but I would hardly call it the end all be all of gameplay. I choose it initially over 2K5 because it had accelerated clock which made possession time more realistic and I enjoyed the franchise options such as relocation and firing/hiring coaches. However I get a little antsy when people speak of 05's superior gameplay. First of all, 05 needed a user fix (The Manefesto) to make it playable. Without it, you ran into the defense "first against the run. last against the pass" glitch because every CPU opponent would use an 80% pass to 20% run ratio. Secondly, the over-exagerated speed and leaps by DB's and LB's in a passing situation were basically born out of 05. Lastly, and this killed me the most, 05 lacked major portions of basic football...mainly the limited options on coach's challenges and pass interference (it still baffles me how pass interference can be eliminated from a game.)
Believe me, I thought 05 was a great Madden and definitely a great step in the right direction. I feel that without competition the ball was dropped and instead of 05 being built upon to make a truly awesome football game we ended up with the joke that is the Madden franchise. Truth is that if I had a backwards compatible PS3 and could get updated rosters for 05 I'd still choose to play it over 2K5, but I feel that when people refer to how awesome 05 was I can give them the same things that a lot of "ballers" say about 2K5 dealing with fond memories making a game better than it really was.