muleshoe,
More like comparing a Honda Accord to a pickup truck, than a Corvette to a Corvair. The Sig is nice, but there are much better. The 22/45 is great, but it's greatness comes from it's association with straight grip guns like the 1911 and Hi Power, and it's truck like toughness. I retired my 22/45 after almost 2 years of heavy shooting ( a bit over 25,000 rounds). Takedown and reassembly of the 22/45 is much easier than the Mark II ( I own both), even though the mechanics are almost the same. My 22/45 is about the same, w/25K rounds, as it was the day it came home except for a little wear of the finish in 1 tiny spot. Function has been close to 100% w/the 22/45 and the only failures I had were ammo related, or due to an accumulation of dirt ( I shoot mostly Rem Thunderbolts, best described as filty). I haven't shot a Sig yet, but handled a couple of them. Nice gun, but the target supplied wasn't anything the 22/45 couldn't do. Early reports on the Sig are not too positive, with a lot of people complaining about reliability. Since I have yet to spring for a Sig, I have to rely on such hear-say to base a decision on. I believe a lot of the extra price for the Sig comes from: It's new, It's Sig and It's hard to get. With a little, it has potential with some trigger work, to shoot close to a Smith Mod 41, or a High Standard. The Rugers can only go so far, due to the design, as far as triggers are concerned. I recently handled a Ruger Mark II full blown Volquestern(sp), with a sub 1# trigger, priced at $600.00. With all the work, it wasn't up to a $700.00 Smith as far as trigger pull, and the Smith had a 3# trigger. ( There is light, and there is silky and light, w/just the right amount of crisp). Don't mean to downgrade the Sig, I want one big time! I just decided to wait a bit for the initial hoopla to drop, and the bugs to get worked out.
FWIW, I replaced the 22/45 with a Buckmark Camper. Same price as the 22/45, and a really nice pointable gun. So far I really like the Camper. I still love my 22/45, but feel it has earned a rest. My $.02 goes to the 22/45. With reasonable care, it should last several lifetimes. The stainless version, even longer. I figure at 25K rounds, mine is just about broke in. Buy the 22/45, and enjoy shooting it while you save up for the Sig. You can't have enough .22's.