Mini guns have improved considerably, and for many people they are now the more sensible purchase. The decision comes down to where you will use it.
The case for a mini
Fits in a bag, weighs a few hundred grams, and is quiet enough to use without announcing it to the room. Amplitude is lower, so it is less suited to heavy leg work — but it is the one you will actually carry.
The case for full size
Longer stroke, stronger stall force, longer battery. If your main use is large muscle groups after training, the extra size earns itself back.
A practical compromise
If you are choosing between the two and cannot decide, consider how often you will travel with it. A gun used three times a week beats a better gun used twice a month.