Haven't had this long and so haven't been able to utilise all its facilities, although first impressions are very good. It is not as difficult to use as I thought, considering my old unit is a Boss BE-5 and is stone age in comparison. Programming sounds into the various banks is easy once you've done it a few times and there are a large number of good sounds built in. You can put the sounds in any order you like, and with four positions (switches) in each bank there is plenty of room to dedicate a whole bank to one song, if, said song has several different sounds in it.
As with any good unit, the device can also be by-passed if you want to play through the amp only.
Thats as far as I have got with the GT-10 and so far I am very impressed.
Only slight downside is that it is quite big and heavy and a decent quality carry case is a must, really.