Kuo's stuff is legit.
Just fyi, Kuo's organization puts a heavy emphasis on training Tantui and Cha Boxing before they take up taiji, so you'll often see a lot of that flavor carrying through.
That being said, as far as the taiji goes, there's a section in the Guang Ping form that is 100 percent identical in a Zhaobao form I've seen....so, take that from it what you will.
Their stuff is first rate and the people from that lineage that I've who I've met that are good are VERY good. It's disseminated to a LOT of people who only do it for health, but it's a real fighting system, so it's a pretty mixed bag. I wouldn't base an opinion on the style by looking at Simu.
FWIW.