In terms of anything - run time, visibility, ease of use (including not switching on in a pocket/bag, weather sealing.
Mine are stowed in my pannier and I've never had either one switch on inadvertently.
Light output for both is excellent, easily visible over a great distance and, I reckon, over 180 degrees.
The Booster has a hidden switch on its underside (not visible in the picture) which is flush with the housing. In fact, it's a small rubber area which is easy enough to press with bare fingers but a little trickier with winter gloves on. Definitely not one you could activate while on the move, unlike the Dual. Can't remember the cycle of modes but there's a steady mode and at least one flashing mode using its three LEDs.
The Dual has a button in the centre of the unit, between the two LEDs. Easy to activate with or without gloves, and despite the more prominent switch I've never had one switch on accidentally in a bag or pocket. Again, this has steady and flashing modes but I'll need to check what they are once I get home.
They are both well-sealed against the elements and have survived several years of dreich Glasgow weather unscathed. The red plastic housing snaps very tightly against the rubber seal so there's probably no need to do what I do with lesser seals and smear a wee bit of Vaseline around them. The only other thing I can think of at the moment is that they both use the same mount.