Despite having a lot of experience travelling independently, I decided to do a group tour for part of my vacation to Argentina and Brazil, for many reasons. First, my travel partner had never been outside of North America (and had never backpacked either) so I thought a group tour would make him more comfortable. Second, we only had 2 weeks, so it seemed easier to have a company arrange all our transportation and hotels (and would result in less potential disagreements about what to do). And third, we spoke no Portuguese. In order to have some independent time, we booked a shorter tour and explored Buenos Aires and some of Rio de Janeiro on our own.
We chose Gap Adventures, now known as G Adventures, because of their reputation and because I had travelled with them to Peru in 2007 (and had a positive experience).
I think some people (especially experienced travellers) hear “group tour” and automatically think lame. But there are pros and cons to them.
The biggest pro is the organization and time savings. Transportation from one place to another is a breeze since you often get private transportation from door to door. Another is having a local tour guide who is experienced with the culture and knowledgeable about the destinations and can impart a lot of history and stories that you wouldn’t get travelling independently.
The biggest cons are the cost and the lack of control over itinerary. If we did it on our own we woud have spent more time in Buenos Aires and Ihla Grande and less time in Rio. Another con is the lack of consistentcy with hotel quality. We had filthy hotels in Paraty, Buenos Aires and Rio but excellent hotels in Ihla Grande and Iguazu.
So it’s ultimately up to you if you want to do a group tour. I would recommend it for some destinations and not for others, but I would definitely be up for doing a group tour again in the future.