Featureless- I already shoot and load 9mm. Having a carbine and a pistol that take the same gun food is a quirk of mine. On my bingo list still is a lever gun in 45colt and contrariwise a pair of single action revolvers in .357. The versatility is a bit more broad. I do shoot .223 in my target rifle, but that is all that it shoots (Ruger mini14 target model) but let me see if i can sum up my feelings-
Reloading- Straight Walled carts are generally easier to reload
Ammo buying- .223 is cheap and plentiful but 9mm is too and the variety in self defense rounds is nice. You can plink, protect your home or hunt for small game easily without going broke buying ammo
accessorizing- I was never really all that into the AR platform until I started to learn how customizable it is. I could have different barrels and muzzle accessories for different uses without breaking the bank and use all the other geegaws and doodads if i want to.
low profile- Let's just say I am hedging my bets, just in case legislation comes down the pipe restricting what caliber ammo a civvie can use. (unlikely but ya never know, also I am only slightly paranoid once in a while)
Yankee- You are totes right there are other options and I love them all. i really want the new Ruger PCC especially since I can get an adapter to take my pistol mags, and I really want a Hi-Point Carbine in either 45 or 10mm. I already have all the replacement rails, mag release bits and what not in a shopping cart for the HiPoint
The Ruger PCC is damned scarce on the ground around here, they are on back order pretty much everywhere and they are reasonable but still outside my immediate budget so I figure I will wait a bit and get one later. The AR build I can go bit by bit each pay check. I am looking at one of PSA's lowers but they NEVER seem to have uppers in stock and they claim that you need to match their 9mm lowers with their specific uppers. I have heard that this might not be true.
Barrel length- I like long barreled PCCs, carbines, scout guns etc. My lever gun is roughly 36" overall and that's the general dimension I am aiming for.
Never smile too big, the gods may mistake it for hubris.