I've had a phaeton for the last 2 years - so can't really comment on the long-term durability of the build.
But I've used it on expeditions and camping trips, using a set of two 18650's for about 2.5 days caving on a mix of setting 1 for camp, and setting 2 for normal caving, with here and there bursts of the brighter settings for large passages. I've not had any problems with it, so I highly rate it. It's reliable and water proof, and you can get more 18650's to build your set of spare batteries. I also like the low-key functional design of the lamp. The switching on/off with the piezoelectric switch can be fiddly to 'get' at first, but there are no moving parts, so once you get past the 'press three times at the right rhythm business', you can get the full functionality even with extremely thick, muddy gloves.
Has anyone got experience with the after-sales side of things?