the XP60 and XP80 are the same exept the XP80 has more keys! Both models are basically never versions of the XP50 although i have found the XP60 better than the XP50 and owned both. The sounds are basically the same althought the XP60 is easier to use due to the more comprehensive display ( it might have more editing functions....not too sure) I would say the sequencer is a bitch to use if you are hoping to do Hiphop and complecated beats...but then only a computer sequencer will really stand up to doing the job properly for editing etc..I think the XP60 is a good alround synth, though if you are going to use an external sequencer get the XP30 as it has the session and techno boards boult in....the techno board is vital for good sounds for hiphop!!