Okay, visited their website for awhile...
Yep, it's a forged receiver... that's what the "Plus" stands for. Forged receivers are milled, so you're good to go, there.
Your barrel will behave just like your SU's barrel - just break it in properly and you're in business.
Is it a better rifle? Well, that depends! It's a different rifle.
The SU is great because it's superlight, folds to a compact size, is reliable, and accurate enough to make a great HDR (Homeland Defense Rifle). You can take it places you can't take an AR. It's usually much less expensive, and takes AR mags.
The AR, on the other hand, I believe to be the best military rifle ever designed. Lots of folks badmouth the AR, but I've come to the conclusion they only do so because they're embarrased that their M1-A1, H&K, or whatever other military rifle they possess is out-performed by the AR.
The AR-15 may very well be the single most reliable personal firearm ever designed. Add near-match accuracy and unbelievable durability to that and you can't go wrong.
If it came down to the question "Which rifle do I grab" when the looting starts and bullets go whizzing by it's a no-brainer - the AR. It can take the pounding the SU can't.
I've owned civilian versions of darned near every military rifle offered to the public, and the AR has beaten them ALL out, including such guns as the Steyr AUG and Israeli Galil. I still LIKE my other "black" guns....
But when the SHTF, it's my AR I'm grabbing.
Flyer