I don't have as much time in this game as a lot of the more seasoned members of this forum, but as I continue on my voyage of discovery I am quickly realizing what I like and don't like - and I really like a 9mm 1911. I have a .45 Ronin and a 9MM RO Target, among others, and I have put way more rounds through the Range Officer than the Ronin. Honestly, I'm not a big fan of the recoil of the .45, which I think is because I learned to shoot using 9mm. I suspect that if I had been shooting .45 from the start I may feel differently. I wouldn't dream of trying to convince the die hard .45 1911 folks to switch, but I would definitely encourage them to try a 9mm 1911 if they get a chance, they might be pleasantly surprised.
Went to the range with a friend and fired his 5" Ronin .45. Found it to be accurate and not unpleasant to shoot. We ran 400+ flawless rounds through it to help break it in. Job done. Then I tried his Ruger 9mm SR 1911. It was like shooting a .22! I found it to be very accurate and fit like a leather glove. I was going to look for a Ronin, but decided to go for the RO 9mm Target in SS due to getting a really great price. Cant wait to go with him and compare both brands of taget model 1911s.
I dont feel 9mm is better than .45 or visa versa in a 1911. I cant speak for 10mm. My only thoughts would be that 10mm caliber is for serious serious business and the least likely failure rate and therefore highest reliability might come in the form of an XD, Xdm, M&P or Glock striker fired pistol.
I never saw the utility of firing a 9mm in the 1911 until I tried it. I dont think I'll replace my EDCs, car or bedside guns with a 1911 since I have M&Ps, SA Xds and Glock striker pistols for that purpose, but that 1911 is American vintage history and is going to get shot and driven around a lot on weekends.