I've only used EQ6, so I'm biased. But I am soooo going to borrow "futz"! ;-)
The biggest thing about EQ6 is that you really do need to spend the time doing the tutorials and working your way through. Otherwise it's like buying a car with 5 gears and then only ever using 1st.
Whether it's worth the money or not really depends on exactly how heavily you want to use it.
If you want something that will figure out your yardage on simple quilts once or twice a year, go for the cheaper one. But if you're likely to get hooked on complicated patterns (like pittsburgpam's starred and feathered quilt) then I think it's worth spending the extra. I have done a lot of playing, designing quilts I'll probably never make. But I've also used it for quilts I have made, planning from the very start or scanning blocks in halfway through and figuring out which border looks best to finish.