First,
What are you doing up at quarter to 5 on the computer thinking about guns
I just bought a PARA S16-40ER. I don't have the Glocks or a Sig, so all I can offer is the observations from a new Para owner. The one I bought is a covert black model.
Reliability.
I have put a little over 400 rounds of Winchester 165g target ammothrough it with no FTF or missfeeds (that weren't induced by me not racking the slide correctly.)
Accuracy
The gun is accurate, although its owner is not.
Fit and Finish.
The slide is very tight to the frame and after 400 rounds it is still very tight. The coating is... a coating. It is evenly applied, but is is not as pretty as a blued or polished stainless gun. The main spring housing and magazine release are plastic, but this is not necessarily a problem, just an FYI.
The hammer, sear, disconnector, slide stop, thumb safety, and grip saftey are all metal injection molded (MIM) parts. Again, this is not all bad, MIM parts are less expensive to make and keep the cost of the gun down, but they can't hold a temper like machined from billet material can. This makes them less than ideal for hammers, sears, and disconnectors.
I contacted a gunsmith to have the 7 lb trigger pull worked on, and got a quote for over $200 because he wouldn't work on the stock MIM parts and would have to replace them. I bought a kit from Cylinder & Slide, tweaked my sear and disconnector spring and I now have a 2.5 lb pull, and parts that will last a long time.
The double stack fits my hand nicely.
Platform.
You can't go wrong with the 1911 platform. The genius of the design, its functionallity, and the crisp trigger are some of the reasons it has been around for a hundred years. There are a ton on dealers out there making parts for the 1911 and its variants. I shop at First Defence and they carry Wilson Combat and Ed Brown parts. These are for the most part, drop in pieces; however, there are some things that will need a gunsmith to install.
What I have done already:
New FO sight
Hammer
Sear
Disconnetor
Main Spring
Sear, disconnector, and saftey spring.
80 series trigger kit from C&S
More on the way...
I have drifted off your original question. I have shot USPSA style courses of fire a couple of times and like the PARA. It is a solid platform, but you should expect to put a few $$$ into it to make it competative, or let someone else do all the work and then buy it used.
BTW, PARA sells a frame kit, You build your own gun!