I'm mandated by department policy to carry a 1911 for SWAT, and have been using a duty treat Specialist for that for 3 or 4 years. I have 6,000+ rounds through mine. It runs great, and the duty treat holds up extremely well. Here are some current pics of mine. It still looks basically new.
The only issue I've ever had with it was in May of this year, and I noticed that the right-side safety was a little loose and wasn't sitting flush with the frame. DW sent me a prepaid label and I had the gun back in a week and a half with a new safety, no questions asked.
For the price, and the features on the gun, I think the Specialist is one of the best values in the 1911 world (ambi safety, magwell, rail, Clark rib, ball end mill cuts, Straight 8 sights, etc).
I like to collect 1911's (and S&W revolvers), and have had a LOT of DW 1911's-- like 18 of them. I've also had/have multiple Wilsons, Les Baers, and an Ed Brown. I like the DW's as much as any of them, and more than the Baers. Even with all those DW's, I've never had any problems with any of them functioning, but I can't say the same about the others. I did have a few DW's that shot high, but Dan Wesson put a new front sight on them each time with no charge.
In 2015, there were some issues with the bare stainless DW's galling, but you don't here about it much anymore. Usually, when you hear about it now, it's because the gun wasn't being run wet enough, which is a must with a tight stainless on stainless gun.
You mentioned you were also thinking about a Sig-- If you're talking about a Sig 1911, I would pick the DW without a second thought. I'm issued a Sig 1911, and I do not care for that gun at all.