It seems to me people are more inclined to complain rather than praise anything these days. My experience of Ultrafire is not very long term as I have only had them for about 6 months, but is as follows:
WF-501B with Cree R2 - Working perfectly, 200+ Lm great thrower (from UK importer)
WF-501B with Luxeon K2 - Red LED, very bright mainly used for Lamping (from DX)
WF-501B with 5 mode Q5 - Working perfectly nearly as bright as R2, then fitted 0-100% ramping Cree R2 drop-in, still working perfectly (both from DX)
WF-501B with Luxeon K2 - LED output unacceptable but otherwise fine. DX replaced fully FOC, now in drawer as spare host.
WF-501B with Luxeon K2 - replacement working perfectly (from DX)
UF-H2 - nice torch, the only complaint being the battery cap is too tight using regular AAs - why didn't they make it 1mm longer - suffers from parasitic drain when left off, so needs the battery cap unscrewed if left for longer periods. Nice and bright on 14500 (From Ebay)
UF-H3 - Excellent floodlight/ headlamp running off 18650. Very bright great battery life, does not suffer from parasitic drain (that I have noticed so far) but this is probably due to the full off switch in this bigger model.
These are all running on Ultrafire protected and un-protected cells.
As I have so many, none of them have had really heavy use, but have been used regularly without any problems. Only the Luxeon K2 LED gave any problems, not sure if this is anything to do with Ultrafire or if DX put that module in the WF-501B host.
Oh and one needed the o-rings swapped round as there were two different sizes and they had been put the wrong way round.
I am very pleased with all the Ultrafire torches I have. Yes they are budget, and when compared to Fenix and Quark you can tell the difference, but value for money is excellent.