Tom
The 5 is nice in that you can always upgrade the piece by using the "5" as either a preamp or amp.
I have the "5" and Im currently looking for a 202 preamp thereby using the 5 as an amp until Im ready to upgrade the amp.
Muzikat pretty much summed it up in terms of sonics. If you have no plans to upgrade , dont have vinyl, and prefer a more aggresive sound, go withthe 5i.