+1. You don't want to pay the big bucks for a general review of geometry that could be covered in a group class. The expensive personalized instruction is more useful for the kid who is already at the 90th or 95th percentile and needs to pinpoint remaining weaknesses (usually companies will do this by testing at the start of the tutoring) so you can knock off those remaining problems.
Beyond that, I think a lot of it will come down to the actual tutor the company assigns to you. Company X could be great for one family, but maybe that same tutor isn't available for your kid. Also, DC tried a company that promised testing and then "individualized" tutoring within a group if 4 kids, but it wasn't that helpful because the group moved together at the pace of the slowest kid - it wasn't one of the companies mentioned above.