I have an LTC that I purchased a few weeks ago. It is the one with the steel frame. I was really interested in the new extractor design, so that was the main reason I purchased it.
The cosmetics issue aside (I like the look, a lot of people don't), it has functioned for me flawlessly so far. I put another 100 rounds through it this last weekend, for a total so far of 650. It has never failed to feed, fire, or eject. I am still using the stock magazines with it, and they function perfectly too.
This is the first Para I have ever had. With this limited experience, I can't make good generaliztions about the brand, but so far, this pistol has been very nice. I obviously have not had to use the customer service facilities at PO, so no information there.
The only complaint I have, and it is nit-picking a little (but with no function issues to complain about, I have to find SOMETHING!) is that the grip safety is a little loose. It funtions fine, but has a little more play than any of my other 1911s.
I trust steel frames a little more than alloy. I think the general consensus is that they will last longer, but a good alloy frame will probably outlast you!
The main thing I think is weight -- the alloy will shave some ounces off if that is a concern for you. (It isn't for me -- I use good leather and belt, and never really noticed the weight one way or another -- YMMV).
Hope this helps.