When I bought my PT145 it was the thinnest 45 ACP I could find with a ten shot magazine. Near as I can tell it still is. I also like the mini frame that Taurus uses in the milpro - to me that's the best mix of metal and plastic and wears more like a steel slide on a full alloy frame. The Kahr CW45 is about the same width - maybe a little less - but it doesn't carry the capacity. Officers model 45's have the same limited capacity, along with a fatter grip. The Stoeger Cougar in 45 gets close to the capacity, but the ambi controls make it kind of a fat boy, and the long grip is more difficult to conceal. There's the Glock 30 - you get 10 rounds but you're packin' a porker. And none of them can touch the milpros trigger, IMHO.
Every time I go looking for compact 45's I come back around to the conclusion I originally reached - the milpros are hard to beat. Personally I think the biggest threat to the milpros is the 800 compact line, but they lack the full mini frame, and they haven't come out with an 845 C yet. And again, I like the full mini frame. I think Taurus definitely got the milpros right.