Chris pretty much summed it up.
I'm currently using a stock rocky with a stock Silvia. (stock?! how shameful!) I have been lucky enough to have been loaned a mini a while ago by one of the baristi at my old job and, just last week, a mini-E. To me, there is a significant difference in adjustibility. With the Rocky, I'm often at one notch and need to move up or down just a teensy bit. I'll change it one notch and vary the dose to try and compensate for the steps and, invariably, end up completely wrong (but less than if I had just tried to use the steps). It usually takes me about three shots to dial in the Rocky properly. By contrast, with the mazzers I just dial and am at the right spot for the second shot. A fair bit of the time, when changing beans, I'm able to just move a notch or two and get pretty close. The only real difficulty is that sometimes I have a complete brain seizure and move the collar in the wrong direction ;P Perhaps this advantage is because I'm able to shoot for a consistent dose, or perhaps I've just developed a bit of an affinity for the mazzer parallel burr grinders by having used them in a cafe environment.
As for doser v doserless, each are good, but in different ways. If you're prepared to do the duct tape and cup mods on the super jolly, I think you'll find it quite convenient for home use. It's neat to be able to grind into the doser whilst doing other stuff, come back, flick the switch and get your dosing done in a few seconds, rather than standing there holding the PF.
The mazzer spring system holds the burrs much more solidly than the pin thing on the Rocky. If you're pedantic enough to tape the burrs in the first place - I am, too - you'll appreciate the spring support system.
I'm sure that you're aware that the mazzer hoppers aren't the greatest for home use.