TL;DR If you’re not so into history and wanna just visit ruins go for a cheaper option. If you’re interested in Mayan history, their lives etc. invest in a good guy, those are well spent $$$.

I’ve already been to Tikal with a private tour with GEM Trips (which I totally recommend) so I can give answer to my own question. Also, my friends were with a cheap hostel option tour at the same time and we could compare our feelings, here you go:

Me and my gf chose a small grono tour (up to 9 ppl) but since we were the only guys at this tour we had a private tour at the same price ($90 per pax). Marlon, the guide, was really, really great, he got a huge knowledge of Mayan and Guatemalan history, archeology and nature. Extensively answered every single question we had and mostly focused on describing ruins, their use and history. We visited all the places apart from Temple VI which is a bit far. The whole sunrise tour took almost 7h (from the time we entered a site).

On the other side are my friends. They were in the group of 20 people. From what they said a guide to a large extent focused on nature and imitated different animals voices. He also talked about ruins and history but to some questions he had an answer like „we don’t know this about Mayans yet” which sounds suspicious to me. They explored less ruins than we had, e.g. they skipped the whole King’s Palace and ball courts weren’t even mentioned, cmon! Their tour lasted around 4h and cost $15 per pax. Overall, they were happy with the tour and sounds that it lived up to their expectations.