#33 tiller vs #450/647 tiller

OK, I know this is out of season but with all the warm weather it has me thinking about spring tilling.

My question is has anyone had personal experience using both a #33 tiller behind say a 140 vs a #450 tiller on a 425 or a 647 tiller? The problem I have is that I have a 425 with 3pt and pto but I picked up a #33 tiller for $20. It would probably be cheaper to find a 140 and use the #33 but does the 450/647 to a better job? And do the ergonomics of the 425 make it superior enough to be worth the extra cost?

I used to have a Cub Cadet 149 with a #2 tiller that worked OK but not real smooth and didn't cut that well. I would assume the #33 would be about the same. I guess I am wondering if the newer tillers are more commercial like where you just drive up on untouched soil, drop it down and end up with a nice seed bed.

Thanks