Jan 2004 we stayed in 200 and really liked it. It is an easy walk to the settlement bus stop or the marina. Oct 2007 we stayed in 400 and liked it even better. It is about the same walking/biking distance as 200. The only problems I had with 400 were the noisy drunks on the goof carts at night. Our site backed up to the main road so request one on the inside of this loop.
I have no experience with 100 except I wouldn't like it because of all of the foot traffic(people from 200,

400, etc...) using it to cut through. There is a foot/bike path you can use in loop 100 to cut down on your walk to the boats and we used it often when we were in loops 200 and 400. We stayed in loop 1400 in Jan 2008 and it is great, EXCEPT for FW bus service. It is a little far to walk to the settlement and boats, not a bad bike ride though. The sites are really big and there is a great place for the kids to play ball at the entrance to this loop.
The bus service in FW is terrible anymore. They have a new system and it stinks! Our avg. wait time in Jan. was 20 minutes or more just to get a bus from our loop to take to the outpost or settlement. Golf carts are great because it doesn't really matter what loop you stay in and you wouldn't have to worry about catching a bus at your loop. That is if you can bring one from home. You would have to be retarded or drunk to rent one in Orlando or at FW. It is NOT worth the price, but that is
just my humble opinion!
My request for our Aug./Sept. 2008 trip will be loop 400 first then 200(never again 1400 because of the bus service). Oh btw, we are animal lovers who hate pet loops(not that it seems to matter anymore!) so 700 is out of the question but it is a great loop too!
Best of luck and I hope you have a great trip!