In FRC, the game is released in January, and the world championship is in April. This 4 month period is the season, while the 8 months from May to December are considered the "off-season" because that is a time when teams recruit new people, experiment with new projects, and host off-season competitions, which are like practice competitions for the real season. I do FRC over VEX mainly because the robots are bigger and more exciting. VEX has a better interface and overall program (and I do actually do VEX V5 on team 920B), but I find FRC more enjoyable.