The main difference between the Vivaldi and the Mini Vivaldi is that the former is a plumb-in model, the latter has a water reservoir. The Mini has a vibratory pump because a rotary pump cannot work without a constant water source (someone chime in here for better explanation). The vibratory pump is a little louder than the rotary, but a whole lot less noisy than any grinder! Haha!
BUT, that has nothing to do with brewing and steaming at the same time. Both units are double boilers and brew/steam simultaneously. I have the exact same Mini Vivaldi and it steams exceptionally well.
That said, I think brewing and steaming at the same time is overrated. When brewing, I'm watching the coffee flow and manually stop the brewing (as opposed to letting the machine stop itself, ala volumetric dosing). So I wait the ~25 seconds to finish the shot before steaming.
The real value (for me anyways) in a double boiler (and heat exchanger), in terms of brewing/steaming, is that you can steam immediately after/before brewing. Single boilers require time for the temperature to change from brew temp to steam temp.
Bottom line, if you have any plans for plumbing in, get the Vivaldi. You can get a
Flojet system to feed water until you can tap into a permanent water source. But if plumb-in is not an option, get the Mini. I love mine and you'll be surprised how easy it is to make great espresso.
Here's a pic of mine!
