I've owned two different minis over the years and they were OK. Accuracy was not great, maybe 5 or 6 inches at 100 yds, and I have other rifles I can shoot better. I hear the new ones can cut that in half. The new target version looks like something an ape from the future would shoot at Chuck Heston with from horseback (or at Mark Wahlberg in the more recent version of the movie).
Mine worked perfect with factory 5 rd mags and quality commercial ammo. I got rid of them before all the recent Wolf ammo (steel case, etc) so have no comment on that. Factory reloaded ammo gave mine heartburn on more than one occasion. I had factory 20 rd mags that worked great.
I would kinda like to have one for casual plinking, but cannot justify the expense when an AR kit and stripped lower are about the same price, or a CMP Garand for that matter. The real show stopper for me is that I could buy an SKS for so much cheaper.
My buddy had a mini-30 and it was alright at best. Accuracy was minute of pie-plate at 50 yds. Non-factory mags were a waste of time and money. It locked up twice - gas block to op rod (or whatever Ruger calls that part - op rod, bolt carrier, I don't know). This was in a low humidity environment. Too much oil on the carrier might be the cause (?) - I think a rubber mallet would be a good accessory for your toolkit if you buy one.
The minis are the right look, right package, right cartridge, right feel and balance - but made to be cheap to manufacture and an overall compromise for the buyer. Depending on what you need the rifle for and what you expect it to do you might be very happy.
No decent hi-cap mags can be found to my knowledge - maybe that has changed. The issues discussed on THR about Bill Ruger and the current Ruger leadership and gun control can be debated endlessly - let's see Ruger market some decent 20 and 30 round factory mags that work and then I will stand down on my suspicions and feel better about the company.
They seem to hold value so if you buy one and don't like it, you can probably recoup much of your investment. I'd recommend trying a recent manufacture mini, and let us know what you think and how it works for you. Life is too short to agonize over a decison that is largely reversable.