Originally Posted by Whatsitoosit

If you plan on using this midi keyboard for playing real piano sounds and/or entire pieces of music involving piano, I would recommend getting the M-audio with 88 keys. Otherwise you will be frustrated trying to play an entire song with half of the octaves not present. If you are just looking to make funky sounds to record with and won't need the entire span of a real piano... then 49 - 61 keys will be fine.