I have an R5M Long .25 cal in walnut. It is a joy to shoot, accurate, easy to work on, robust, quiet, and good looking to top it off. Mine came with an EDMU that functioned for a couple of days and then gave up. It's a cleaver device, with shot count, air used in last shot, remaining pressure, and some other stuff. I replaced it with an Wika analog gauge from Edgun West Brian, who by the way is a super guy, interesting & helpful. In fairness, I have a Leshiy with the previous generation EDMU that has functioned fine since I bought the gun 8 or 9 months ago.
The smooth-acting charging handle of the Matador is easy to operate, never miss loading a pellet, but it is easy to short cycle on the way home. The whiff of air on your cheek when you fire will tell when that happens. It just doesn't fall home by itself when you close the bolt. The last little part of the return stroke takes a bit of force to push the charging handle home and get the *click*. Once you get the feel, it's not a problem.
I have not done anything with tuning. The gun has had 5 or 600 shots through it and a couple of cleanings. The week I ordered an Huma reg kit from Brian. Compared to the Leshiy, it is a bit of a hassle to adjust the hammer spring because you must remove the stock, but that it only takes a minute of two. It's not a big complaint at all.
I've had mine for 3 or 4 months. IF given the chance to redo the purchase after getting to know the gun, I would do it without hesitation. Yeah, it's a bunch of money. by the time you put good glass on it, get a new tripod (always with a new gun, right?), install the bottom pic rail, and buy a dedicated case, you'll have close to if not more than $2500 in it. BUT, it doesn't take a material scientist or destructive testing engineer to figure out the Matador is an heirloom quality gun that you can pass down to one of your fine kids for them to pass it down to one of the next generation. Hyperbole? Well, maybe a little, but it is a super gun.
Can't wait to get out for some sage rat fun.