one of our tt riders used these for about 3 races and about 5 training rides, call it about 20 to 30 hours of riding. they were on an SRM we just sold where the customer wanted 53/39 rings.
This is a 54/39 which works great. give you a big gear for the flats, but that nice comfy 39 when climbing, cooling down or warming up. Shifting is perfect, we've been running 54/39s on our TT and Crit rigs for quite some time without ever an issue. Its not a stock Shimano gearing but it works great and is very functional.
you can see the rings in the attached photos
Asking $90 bucks shipped for the set.