I know that some teams are just starting and that having a good table is important. I'd like to give a shout out to the Republic of Pi for their YouTube video highlighting a fantastic portable FLL table.
We built this table last year, after trying both the standard plywood table *and* a foam table and I can say with confidence that this is the best table to build if you have somewhat limited space and might need to move between houses. In addition, it was easy to store in the offseason. The single-best design feature of this table is the 6" "shelf" that allows us to setup the shared mission model without any hassle. It's well worth it.
If you decide you want to build this table, feel free to contact me off-list and I can share our experience and some build tips that may not be obvious from the video. Note that building this table does require use of a Circular Saw, so it's likely that you'll have a couple of parents building the table while the kids are inside working on robot design/project. We were able to build the entire table in about 3 hours, and the kids can set the whole thing up in about 5 minutes.