Dpm recoil spring system is really good - DPM Walther P99/PPQ M2/Long Slide Mechanical Recoil Reduction System

I was a little skeptical about how much real-world difference the DPM system would make for me.
It made a lot.
I use it in both a Walther PPQ M1 4" and a Walther PDP compact with 4" barrel.

Am I more comfortable? Yes. Perceived recoil feels reduced in maximum intensity and more importantly the recoil power curve seems to be spread out over a longer time, and maybe flatter. In both pistol recoil is easier to live with and to manage without a doubt.
Also, the slide does not "hit" my wrist as badly when it reaches maximum travel, and this is especially noticed with hot EDC loads, +P, and NATO loads--especially on those good days when my stance, grip, and wrists are locked right down. There is much less "teeth rattling" and there is less tendency to for carpal tunnel aggravation while the recoil transmits down to the ground.
Overall, I can shoot more rounds in a day with less distraction.

Am I shooting more accurately? Yes, in rapid fire. Definitely when comparing any of the 3 DPM springs to the worn OEM spring there is a difference. I may be more accurate when shooting the heaviest spring compared to a new OEM spring (polymer rod)--they are in a similar or same ballpark as far as accuracy goes, but the DPM is more comfortable and seems to make body stress more tolerable. I plan to check this again but using a Mantis X10 system to try to generate data in this regard.

The non-captured springs are not at all hard to install or swap out once you figure out where your fingers go to do it. I don't even look or pay attention to that step anymore. it is no more difficult than changing a captured recoil system, just don't lose the spring cup.

The springs and rods are very high quality and have fairly fine polished finishes. They are very smooth when manually actuated.The adapter cup does not seem to be high quality. It is thin, has sharp edges and although it is blue-black it does not seem to have a surface treatment. If it does, it is really uneven and perhaps an incomplete one. I keep it oiled up. There have been no issues with the sliding guide rod gumming up or collecting residue--probably because the surface is so shiny.

Recommendations:
If you are replacing a worn OEM spring, this is a great replacement.
If you have new OEM guide rod and spring and you want to improve the perceived recoil, or you want to try to protect your wrists, or you want to try to get just a little more edge on muzzle control, the DPM is a worthy investment. For Sure. No Doubt. It isn't magic, but it helps. If you have beginner-level technique this won't improve that, but it may make it easier to get through all the rounds it takes to get better.