Para does not exist any more, so if you're looking at Para you must be looking at used, or VERY old shelf stock. ParaUSA was bought out by Remington, and they killed off the Para name and the double stack pistols, and sold off all the parts inventory to Numrich and Sarco.
Word at this year's SHOT Show was that Remington will be bringing back a few of the double stack pistols later this year, under the Remington name. Haven't seen anything yet.
I've owned a few Paras over the years (all but one of mine were Para-Ordnance, made in Canada) and I'm a fanboy, but I'd have to say that most people would rate STI better than para.