When I started my long haul travels in 2016, I joined the Ultimate Africa Tour by G Adventures. It was one of the best trips of my life. Since then I have used them and others for group tours. I have mixed these with independent travel. I have found group tours to be excellent for meeting a lot of like minded travellers, exploring a lot of places in a short period of time, being able to travel without worrying about logistics, being able to explore ‘less accessible’ places and for being able to plan very much in advance. At the same time, group tours are quite expensive as many do not cover meals and are quite rigid in their itineraries which isn,t great if you want to spend a few more days in a particular place. Given my budget is much lower for future travels, I would probably use group tours for specific activities such as certain treks in Patagonia/navigating ‘less accessible places’.
An older post reflects some of these sentiments (before my long haul travel in 2016): My thoughts
Tour Companies I have used before
G Adventures: http://www.gadventures.com
Adventure Tours: https://www.adventuretours.com.au/
Tour Companies I have not used but friend have and they loved it!
On the Go: https://www.onthegotours.com/
There are of course, a lot more travel companies which cater to large groups, party tours, luxury tours etc. I don’t enjoy the idea of being on any of these tours and so I havent really looked at any of these.