Circle can run troops too or a mix fairly well. Trolls just don't run beasts well.
Bear in mind that even a troop heavy list will need 2-3 warbeasts to generate fury from.
Painting is fun on occasion, however I have never met anyone who enjoys painting hordes of models. It is a bit of a chore even if you like painting...
Best advice would be to find someone to split the two player box with if you go circle. Trolls are not so lucky but as far as I am aware their starter box is pretty good if a little redundant.
The Privateer press forums are relatively active and have a lot of good advice on them.
Battlecollege is also a good source of information, it has reviews of every model in the game with a breakdown of each ability. Not something to rely on if you are a tournament level player but for a beginner it is excellent.