I much prefer a mini reflex sight to a mini red dot on a pistol. For me, they are far quicker to pick up the dot with. I have a Trijicon RMR, a Deltapoint, a Fast Fire III and two different Primary Arms mini reflex sights. They all have their strengths and weaknesses, but I honestly think the FFIII may be the best suited for a 22 fun gun.
The Delta has far and away the best glass (ZERO distortion and no tint) and I love the 7MOA triangle. The wide window/lense seems bigger than it is too. But....The adjustment screws are tiny and require a very small Torx driver, making zeroing tedious. Also, the sight has to be removed to change the battery.
The RMR has a ruggedness that is super confidence inspiring and has great adjustment screws that make zeroing easy. The glass has a fair bit of distortion and the tint is pronounced though. This one also has to be removed to access the battery.
The FFIII has glass that's between the Deltapoint and the RMR in terms of clarity, has great click adjustments, a battery that accessed from the top, and a price that's half of the other two. It's not as rugged as the other two, nor does it as finely crafted.
I do know that glass quality shouldn't factor as high as it does for me, but to tell the truth, I haven't been able to fully train myself to NOT look through the glass. The thin-ish lense frame and big clear glass of the Deltapoint actually make it easier to do what you're supposed to do and transpose the "dot" onto the target with both eyes open. The very thin frame around the FFIII's helps with this too, but when you do inevitably look THROUGH it, the tint and distortion aren't nearly as distracting as with the RMR. I'll also add that having the sight mounted more forward on the gun helps me pick up the dot faster. I noticed this with my 2211 that had the Deltapoint fully rearward. After shooting my 22/45 that has the FFIII mounted over the ejection port, I ditched the custom mount on the 2211 and moved the sight forward and as low as possible. It's much better for me now.
My Ruger 22/45.
The Ruger I used to draw my conclusions on red dot vs reflex sights.
2211 before.
2211 with sight moved forward (and new dedicated frame).