I did watch the guest GM run, or most of it, and it was a mixed bag. Some of the hosts were actually really great, like Bob Barker as an example, but some of them just didn't seem to know where they were. Ironically, 2 of the worst for me were actual wrestling people- Bret Hart and Ted DiBiase. I seem to remember the Bret Hart episode he came out, cut a shit promo, and they showed it again about 30 times, after which I turned off. The Ted episode was the first time I can remember falling asleep during RAW even though I used to stay up half the night watching it.
Like most things WWE, it was an idea that could have been done right, but they dragged it on way too long, and by the end it got unbearable.