rhyno77...sorry for any confusion my original post concerning the Quest SP may have caused. I just checked my 2010 Exmark catalog and you're right...the Quest (not Quest SP) has the B&S ELS engine and it also has the ZT2800 hydrostatic transaxles, not the ZT3100's and it also has the 4" welded deck instead of the 5" deck. I don't know what price you were quoted on that because there's not one available where I am but it should be considerably cheaper than the 2011 Quest E. The one I've bought (and waiting on delivery still) is the 2010 Quest SP that does have the ZT3100's, the Vanguard with the Donaldson air filter system and the 5" welded deck. The SP costs $4999 (same as this year's Quest Pioneer E) and is closer to the $5999 Pioneer S in specs. The 2010 SP also weighs 100 lbs more than the 2010 Quest.
Just a note...in this area (south Mississippi) it seems like most of the yard services are using some version of the Exmark mowers and there are 3 Exmark dealers within 20 minutes of my house. There are also two Toro, one Scag, one Bad Boy, one Hustler and one Ferris in the area so I've gotten to look at a lot of mowers the last month or so.