I would take a 900 over an 08-09 800. 700 are the same as the 900 sled wise but the bottom end of the engine is the same as the 900. with all these 800 that have blown up in the last few years ride the 700......it will be just fine!
had a 05 900 with over 4000 miles with Zero problems.....NEVER LET ME DOWN! the 700 doesnt have the vibration the 900 had but also had less power! every sled has it problems!
That's not a bad thing, the 06 700s have shown to generally have less problems because of the lesser power and vibration.
In the last couple years, guys have 'figured out' the quirks inherent to making a 900 reliable, and the 700s subsequently.
I would recommend you do as much research as you can on them so that you can be personally informed on all the things that you will want to check and service to ensure a trouble-free season with the sled.
^^^^ you just found your guru^^^^^^^