I was fortunate enough to be given a 'personal' SD5 demonstration from none other than Ajua Alemanji (AJ) himself. The SD5's unique standout is its exciting 'riffs' feature, and 'audio' sample drum loop playback. On balance, I prefer the SD1+ w/ AJ's expansion board though, because I believe AJ's new 'expansion board' raises the SD1+'s sound quality closely competitive with the Yamaha Tyros2 Super Articulation (SA) voices.