It seems awfully-expensive for what it is. The watts (grundfos) system
with the pump and the end-of-line crossover valve and associated hoses is about $200.
http://www.homedepot.com/h_d1/N-5yc...atts+recirculating&storeId=10051#.UQAxVSdtUj0 Ten dollars less in some other places. The replacement valve (or extra valve) alone is about $45. Google Grundfos 595926 "Comfort Valve". The Lobster is, if I understand, basically just the temperature-controlled valve. So its price seems high to me unless I am missing something. For that money, you might as well get the pump, too.
I installed the Grundfos pump and two valves (one for each branch of our hot water system), and it works very, very well. It was 11 degrees out last night, and at the furthest reaches of the house, the tap water in the morning was warm within 2 seconds and hot not much longer thereafter. Before the pump and crossover valves, we would have to run it literally more than a minute on a morning like this before it was anything but ice cold. (Our plumber said, "Just seemed like a minute." Nope. More than a minute. I timed it repeatedly.)
That said, there is NO WAY this thing "saves energy" as the literature would have you believe. The water has cooled more than enough by the time it gets back to the water heater that it isn't going to let you start with "warmer water". As a practical matter, it will come out a cold tap long before it makes it back to the heater, unless it's a very short run in which case the system won't add much. So much of the marketing material on that site is crap. However, with the pump the system does indeed get you hot water much faster than before.