As Jamesy says, hard to learn but reliable. I've just changed from an Elite 6500 4.5-30 back to my 4200 8-32 - but only after getting a mil-dot conversion. Biggest problem is trying to adjust parallax when standing - it's a long reach forward!
The bushy doesn't have much range for adjustment, so it's important to set it up with the turrets in the middle of their range and thenpack the rear turret until you are pretty close on zero at 35yds before you make any adjsutments for elevation on the top turret.
Fit an oversized turret as well: the original "old gold on black" is too small to see. You should get 48 clicks per revolution, and get your 55yd mark at around 5.5 (8 click per major div) from a 35yd zero if ussing tall turrets.
Fit a coaster on the parallax ring to make it a lot easier to dial. The original green distance marks are pretty much spot on but the spacing's too big. I only get about 2mm between 52.5 and 55, but it's repeatable. Only focus onto the target from one direction as well: decide whether to come in from above or below, and then stick to it.
After that it's just practice, practice, practice.