Anyone have experience with Fastlane by Endless Pools

I'm putting in a pool and since building a 25 yard pool would cost a fortune, I want to put in a Fastlane. Does anyone here regularly swim in either a regular Endless Pool, a Fastlane, or other equivalent swim current? www.endlesspools.com/.../index.html Can you give me some feedback on how the workout is, do you feel like you've improved since swimming in it, etc.? Are there any other products like this that can go into an existing pool? Everything else I've seen has it's own small pool it has to go in. Thanks!