We have both and love both. I am bigger and the FS seems to fit better. The wheel base may be longer.
There are advantages to the regular model, namely the luggage rack. I put a Topeak beam rack on
the seat post of my FS, but it only holds 20 lbs, whereas I can ride my kindergarten kid to the bus
on the rack of my non-FS. I have not yet found a kick stand that works on the FS, but I hear
you can find something. I am going to put an internal gear rear hub on one of the bikes, and if you
are going to do that, it is more problematic on the FS because of the rear flex and chain sag, although
it has been done in fine form by one of the fourm users here. Buy one of each, like we did! We are going to buy a third for our son, perhaps one of the later 2006 models.
If you like rear suspension but don't want the other FS issues, get a suspended seat post
like the Thudbuster or similar. You can also get different tires that give you a smooth but efficient ride
without rear suspension. I am no expert yet, but I have been doing lots of reading and research
in the past few months since getting our DT's.