I saw Geoff Tate's Operation Mindcrime last June at the same venue I just saw QR. I'm actually watching my video of it to refresh my memory.
The entire side curatin was down for GT's show, only partially down to block one of the two side bars for QR. I definitely think this was helped by having a support act like John 5 to bring in more people. So not totally fair to compare QR to GT but at the same time, QR was pretty packed and was noted a couple times by Todd.
Geoff is a better entertainer than Todd. Geoff is much more animated and active in his performance. I think Todd however sounds better, not by enough to say I'd rather him in the band over the original singer though. But Todd sounds good and the music they are making with him is solid. It's not a cover band if they are writing and performing original music. It's also not the original QR. However, if Geoff and QR are not able to make it work together, having them both do their own thing is probably the best of both worlds. The QR band sounded much better than GT's band as a whole as well.
Also the comparison of John 5 to QR is a bit unfair. Not really similar music. QR is not bringing an active crowd. The GT show wasn't anymore active. The John 5 crowd wasn't terribly active either until he did the cover medley which brought out familiar riffs (and John 5 himself was animated, calling everyone MoFos
). There was a not a lot of overlap between fan bases either. If people aren't really engaging during the QR set, it's probably because they don't know the songs. I honestly was in this catagory for all of John 5 and about 5 or so QR songs.
Also, you can't see it... but GT did walk by and give me a fist bump coming off stage
https://youtu.be/uSUuazGpcWg?t=1920 other than Casey, none of the QR guys interacted with people after the show that I saw (I could have missed it). Defintiely adds to my opinion that GT is a better entertainer, his shows much more emotion.