@pop22 has some but I'm not sure he or anyone has completed a grow with them yet. I read up on them a bit but decided I'm sticking with cobs. Not because they are better or worse I just have to much invested and don't have the time to try anything new just yet.
A watt is a watt as far as heat is concerned. As for light they are around 50% efficient so 1/2 the wattage is light which is very good. The thing I am unsure of is the intensity. It could be good for lower height restrictions and have a better spread. I'm sure time will prove it's a good source.