it would be fun to know the approx. user quantities of 3dgs, unity and some other game engines too, for each edition (downloads of free, and licences sold yearly). and an estimation of the share of hobbyists, indie developers and companies. really good games are mainly done by teams, and not by a single person, it can also have an effect on how many games released made by an engine.

imo 3dgs is really cool for starting and learning 3d game making, and it's very easy to make small trial projects, and then assemble a simple game from your code and asset pieces. it's a bit old fashioned, reaching pro graphics quality requires complex 3d knowledge, but the price is acceptable also for hobbyists (like me) who live not at the richest part of the planet (I mean of commercial edition). maybe this group is the main target of 3dgs, and the pro edition is rather a shopwindow that shows it is a really professional tool (but in fact pro has some really professional features).

facing unity editor without any 3d knowledge can be a bit frustrating, and you have to deal with and organize a lot of asset and code packages, which needs some practice to be handled fine. but definitely much easier for 3d artists. imo its programming also cool, after I got some experience in delphi, java, and lite-c, I had no problem to do anything I wanted to solve. but for me the free edition is not suitable, and the pro price is well over my budget. but I would rather buy it instead of 3dgs pro.

for small developer teams, I think UDK, Esenthel or maybe Neoaxis also can be an option, but imo they require higher experiences. I like especially Esenthel because it offers both to start from small, and to make an MMO-RPG/FPS based on example game sources available in the shop for a little money (unfortunately its licensing will change to per seat from the current per commercial project).