I was disappointed with the one I rode my XT felt as if it had much more punch through the gears but not as much top end.
I have followed the DD750 & the DD1200 in great detail, they have had many recalls & faults with them the older ones where the worst.
To mention a few.
Coolant leaks
Burn't starter motors
Starter relays
Cutting out stalling.
A few map upgrades
Coolant temp senders
Radiator fans
Throttle sensors
Decompression tensioners
Water pumps
This is one of the best Aprilia forums I have found,
http://www.apriliaforum.com/forums/forum.php