Do it. I was just extolling the CX4's virtues in another thread. I have a 9mm (to go w/ 92FS) and love it; but like the .40S&W much more than the 9mm as a cartridge; if i had to do it again, i'd do .40 instead of 9..and i would have gotten a 96 instead of a 92. But that was then, and this is now.
I also have an old Ruger Ranch Rifle. It is nice (and stainless) but for precision accuracy it is not a contender - the barrel is so thin that with each successive round the point of impact walks up the page and to the right...its a #180-series, and i hear that the newer #580's being sold now have thicker barrels to eliminate this problem.
Between the CX4 and the Mini- the rounds have different characteristics, so i won't go into that - but i will say that the CX4 is smaller, lighter, more ergonomic, mags are cheaper (hey, you've got them already!) ammo is cheaper, and the system is more accurate overall w/ the stock in line with the barrel, like an AR. It is also fully ambidextrous...I'm a lefty...so you can eject to either side and have the charge handle, and the safety and the mag release go to whichever side you prefer. It's also got the rails for all your tacticool gear. I only use the rail that pulls out below the barrel for a laser/light...but there's the potential without a whole aftermarket stock rig you'd need for a mini. Without a folding stock the CX4 can go in the well/compartment over the spare-tire in the trunk of my stationwagon (where it lives, with a trigger lock). Mainly, i use it for rabbits, and the occasional coyote, gophers, etc...pretty much what you'd use the mini- for.
Also, on a corporate note, Beretta is great, and a lot of people have problems with Ruger. The only mags that work well in a Ruger are the factory ones - which are not cheap, and took 5 months to arrive when i ordered 4 of them a while back.
Good luck with it. I don't know you, but I know you'll love a CX4 (especially in .40!).
