I wanted to have just a fun 22LR that was a bit of a form factor equivalent, maybe more of a cousin than a twin. I do have a 9mm AR that I just love, love, love, so maybe that influenced my decision to not just get a 22LR AR, but I built a 10/22 on a Midwest Industries chassis and have been very happy I did.
I will caution that this a step onto a very slippery slope. My initial scheme was to take the rifle I ALREADY HAD, and slip it into the chassis and finish it off with some of the AR furniture I ALREADY HAD, and I lie like that to myself ALL THE TIME!
So I bought the Brownells receiver and a Faxon barrel and the Ruger BX trigger (the only Ruger component in the thing) and to differentiate it (I used green on my 300BO) bought all new grey Magpul stuff, just so it could be a different color. Moved one of my MROs (that I ACTUALLY DID HAVE) over to it, and it didn't like any of the old (the conventional wisdom is the springs get lame) magazines so I bought a batch of new BX-25s, and a Maglula. So the cheap and easy plan worked out just like it always does, but I am happy with the outcome. It just needs one more thing and it will be perfect. But then I would have a spare barrel, soooooo...