I have both. I bought the Derya TM-22 about a year ago and it has been pretty stellar so far. For me it functions with both standard & high velocity ammo, is accurate (I shot a dime size 5 shot group at 25 yards with a 2 MOA red dot) and best of all it seems to have good warranty support from O'Dell Engineering.
I just bought the Adler RF-22 last week. Bear in mind that my opinion so far is based on very limited use but so far I am not impressed. The very first round jammed when I tried to chamber it. After that the 10 rounds (Mini-Mags) did shoot reliably and seemed to be pretty accurate even though I was shooting unsupported. The first round in the next mag also semi-jammed but again the 10 Mini-Mags functioned without a hitch. I then tried shooting some Federal bulk pack from a Butler Creek pinned 25 round mag but could not get any round to chamber although I'm laying the blame for that on the mag, not the gun.
However, when I tried to manually cycle some rounds through the gun from the original mags I noticed that the chambered rounds would extract about half way out of the chamber and then drop off the extractor on to the top of the mag causing a jam. I took the gun home, removed the bolt and inserted a round into the cutout on the bolt face . The extractor seems to exert enough tension to hold the rim but the problem is that the bolt face cutout is too big and allows the case head to move away from under the extractor claw which would explain why the rounds fall off the extractor once most of the round clears the chamber. The originally fired Mini-Mag rounds ejected fine but that obviously was from gas pressure and not the extractor pulling the cases out.
So now I have to contact the dealer I bought it from to see how or if they are going to handle this. If they jerk me around I'll be doing a follow up post.
Overall the gun seems solid and accuracy was decent so I had high hopes for the Adler. Others seem to have had better luck so maybe I just got a lemon. Time will tell but at this stage I can't recommend it. A gun that's cheaper isn't worth the cash savings if it doesn't work.
