I've used Book2Park on multiple trips now. They are legit, reliable, and one of the more affordable options. The parking areas are easy to find, and the customer service is good. I've never felt uneasy with the lots or had problems with anyone messing with my car. Shuttle waits are reasonable but can be a little variable, depending on how far the lot is from the airport. On my most recent return trip, I just missed the shuttle run and had a to wait about 25 minutes for the next one. Some flexibility is required. The drivers have all been friendly and waste no time getting you to where you're going. You can also extend your reservation remotely if you miss a connection or don't return on the expected date. I recommend Book2Park and will continue using the service myself.