LED filament bulbs have been available in the US at Lowes hardware stores for several months and sold under the Feit Electric brand (I bought several and returned them due to their horrible dingy yellow 2200K tint). Also, hundreds of others have been available online for at least a year.
We have a BLF member who has tested dozens of LED bulbs. To his surprise, the filament LED bulb provided the highest lumens per watt advantage above all the others. I have been using a 6 watt 540lm version for 8 hours per night for 6 months, and it has yet to show any lux degradation (verified with my lux meter). I removed the glass envelope to allow open air cooling to the emitter filaments and other tests, so it is unclear if the direct thermal path to the ambient air helps in longevity, but it certainly runs a good deal cooler while uncapped. Hopefully these will prove to be more reliable than the cheap version conventional SMD mounted LED bulbs being offered by Cree, Philips, Sylvania, Feit Electric, GE’s, etc., that have failed so many others within the fist few weeks or months of operation.