I own a yfz and a banshee. I've ridden a few TRX's. I've ridden quite a few of the aftermarket banshee shocks out there.
YFZ shocks are better than stock banshee shocks, but they still blow.
TRX shocks are pretty similar to YFZ shocks
Old style Works are slightly better than stock YFZ/TRX shocks, but are still pretty harsh
TCS is the best bang for the buck when it comes to front suspension
TCS rear is okay, but not great
Axis is cherry, period!
Elkas are good shocks, but I have yet to try one that really impressed me like TCS or Axis
For the price conscious looking for a really sweet setup, I'd recommend TCS up front and something else in the rear. You could save urself some bucks by going with a TCS rear shock rebuild in the rear, but its not nearly as nice. Diesel, even if you buy a new 450 ur still gonna get the shit beat out of you on their stock suspension - ur better off spending the money on arms, swingarm, axle and shocks for your shee. With good suspension, you'll be looking at ur front tires to see if they're even on the ground (its that smooth)!