Not as big of a difference as I thought it would be. This eXmark sh!ts and gits! The acceleration is like night and day. Weight, I'm sure is a factor, as is the increased power. This Series 6 deck could never cut at speed like the XR-7, but the XR-7 could never pool table a nice lawn at 4" (even double cutting!). I'll take the perfect cut over the top speed any day of the week. With the 15/16" center hole (not the normal 5/8") it really limits what's out there. I'll have to shoot Oregon an email about this as a 1/4" thick blade with Fusion would sell like hot cakes IMO.