Other Rainson Edge X .25 Cal.

I know there are previous threads out there with regard to this rifle but.....
I'd like to know who has had one for a while and how life has been with it. I was told by a retailer that they don't know much about tuning experiences since most folks are pretty happy with it "out of the box". I was told that it DOES like heavier ammo but they didn't know how much more the reg could be turned up (if at all) after the factory tune. Please share your complaints, successes, FPS, accuracy, etc. Looking to replace a .25 PCP and I'm hoping this would be an excellent candidate. My plan is to use it for target shooting at 75 yds+.
Thanks!