I was wondering the same thing. I know there's a ton of LDS history in that area but I'm not sure if having an LDS tour guide would speak more toward those historical events or there's something else?
I have not been out with a "regular" tour guide, but as we would stop and get educated on different parts of the sites many, many other people would slowly move our way to hear what our guide was saying. Now that may just be that guide or service, but they were very thorough. Obviously they talk about how some of the other ruins have depictions or carvings similar to what LDS people believe in. It's neat to see historical evidence of things you believe in. Not much different than visiting Jerusalem or something for any Christian. Non-LDS guides would probably not point out those types of seemingly small points. Many of them are hard to see in the carvings unless you are looking at them very closely. Because of deterioration. The other major reason we went with who we did was a referral from friends we trust and I absolutely did not want a huge group/tour bus type of experience. We had six adults and it was great.