I think its more down to personal preference on how it feels in your hands then anything. I upgraded from my original mini to an Axe, then downgrade back to a Mini after my first day playing with it, the only reason was because I preferred how the mini felt in my hands.
I would suggest holding both (with tanks on) and seeing which you prefer, and then if its an Axe go for a second hand one (seen them going as low as £200
) or if its the mini go for the new Empire GS mini which has the better trigger
I'm picking up a new GS as soon as there available ....Might finally be time for me to get an Empire sponsorship