I'm pretty sure that's Tanner's Sport in PA, and they are legit. They are a good price, but it's for the Standard model with the white recticle sites (not so good). So if you're not particular yet and want to get in at a decent price then go for it!
Just know there are two (USG and Tri-Rail) other models and they will cost >$1500.
I also bought mine from them. A first class guy running a first class business. Do not hesitate to spend your money with him. Even if they are not in stock he ships them as soon a he get's them in. I did the BIN on Friday. called him on Saturday, got the FFL in line on Monday. He shipped it on Tuesday and I picked it up in NC on Wednesday.
Tanner's is awesome to do business with and has fast shipping. I just bought one recently from them and nobody can touch them at that price. I was a little hesitant at first, due to the price, but they cured me of that. They are A++. Like others have said, they come with the white reticle, which is pretty worthless, but on this website you can find a dealer who sells a light source which increases the reticle brightness and can be had in colors-Rem 2 or 3 for about $70.00-80.00. I am looking into getting one soon myself.
Just picked up PS90 and two 50 rnd mags from Tannersports....Will be picking it up tomorrow morning.....PS90 was 1275.00 and clips were 60.00 each....Also picked up case of ammo (2000 rnds) for 740.00 shipped. It was a pleasant transaction and fast shipping. Would recommend him to anyone concerned..