Not all are equally interesting!
My favorite bus/tour company is: TB (stands for Transportes de la Bahia) Tours. So far, absolutely no problems. Everything they did was a cut above all the rest!
TTF can be good, but they also missed our hotel pickup for two out of eight tours. If you have time, they will reschedule you, and you should ask for an additional tour free of charge to compensate for the inconvenience.
On one of my trips to the Huichol, the bus broke down (we were met by another bus within 10 minutes), and we were behind schedule. The guide assured us we would miss nothing, but then he skipped the Compostela side-trip I was looking forward to. (I later complained, and was given one of the higher priced trips to San Sebastian free of charge, no hassle). If something goes wrong on your tour, don't hesitate to talk to your booking agent or hotel travel agency.
Be careful which Jungle Tour you choose! The first one took us to a shopping mall for an hour, then toured the city, and finally arrived in the "jungle" (a couple miles off the main highway south). Another Jungle Tour travels south of Mismayolla and Boca la Tomatlan, and is very good. It also takes you up into the jungle at Mismayolla to visit "El Eden", Arnold Schwarzenegger's movie site for Predator. It is very pretty there, but be sure not to miss the little area to one side of the parking area with the bigger waterfall.
All tour guides on the longer tours are very knowledgeable about the areas they visit. I was told they must study and pass tests which cover history, culture, customs, flora and fauna, etc. All guides so far have spoken English, and usually two other languages.
They will often stop at a little stand along the road to buy fruit which they share. You are welcome to buy things there, also.
Vallarta Adventure Tours are good, but I felt their guides were more aloof. I did enjoy their Sierra Madre Expedition, and my daughter took that tour two years later and also liked it. Roads are bumpy, so if you have back problems or similar ailments, skip this tour!
Buses should always be air-conditioned, but may not all have a bathroom. In the off seasons, if only a few people sign up for a tour, a van may be substituted for the usual bus. I booked the Guadalajara bus tour, and a van showed up. It's not quite as comfortable but it was a small group so we stopped at a few extra places. It was almost like a private tour and was enjoyable after all!
Prices vary so ask around! Your hotel, friends, other tourists, they will know.
And, last, but not least, if you enjoyed your tour, tip the guide and driver. If you really didn't think they did a good job (happened to me ONCE only) skip the tip (and don't be embarrassed about it)!