if you want to cut down on maintenace, then a 450 class machine is really not what you want. you prob will have more maintenance than a banshee. oil and valves will have to be your #1 priority and checked and changed frequently (valves checked oil changed). a banshee is pretty bullet proof from the ones we had, but will eat plugs if you are not jetted right. good thing about 07 YFZ is that it has alot of improvements over the 04/05 models. 06 started with over 80 improvements including the bump up in cc's to 449, suspensoion and seat enhancements, etc..the 07 builds on that with further inprovements and the chain adj, starting with the 2006 model, is like hondas (ever wondered why no OEM was doing it like honda and had these dum@ss chain adj proceedures for the last 20yrs: honda had the patent on it and it expired in 2006). and a yfz has no seperate oils like honda, so that will cut down some time, but if i were you id get a raptor. slow or fast- it doesnt care. and get a 700- i know that wasnt in your list but like raptor450 said that is a bit steep for a 2005 model. you can find a 700 for $5500. the 660 is ok and is not impossible to ride but it is noticabley tippy. the 700 also shares some suspension components with the YFZ, so handling is similar. not exact, but wayyyy better than the 660s.