^ he totally stole that answer from me!

I was going to say that the 7.3 is a nice bike too, nice and light frame (like the 7.5) but has 'beefier' tires which will definitely withstand abuse. if you are going to be riding on rough/harsh terrain the majority of the time, i'd go with the 7.3 . the component group on the 7.3 is pretty good too so i would not hesitate to go that route.

the tires specifically on the 7.5 are more geared toward street riding - that is - smoother surfaces. while i am sure they will hold up to some abuse, i would be hesitant to spend $800 to find out for sure