This is a difficult question to answer, it really depends on what you plan on doing with the bike. 4 strokes are definately more expensive to maintain, but in certain applications they are a better bike, as an example, the late model 2t 250's put out as much HP as a 450 4t, but in most track conditions the 4t is superior, why, mainly because of how they put the power to the ground. if your open riding or dune riding, then the 2t's may have the edge. so really the question is like comparing apples to oranges, they are different and each has pro's and con's, you just need to choose for your application. And when I make my comments I'm referring to the late model 450's, not the old XR's DRZ's, KLX's or XT's.