Nice review. Thanks for including the graphs (showing the fall off in lumens over time). I'm sure they take a lot of effort to produce, but they help a lot with the decision making!
I've a Coast HP550. I have it for 2-3 years now. I've not taken it apart, but it appears to be very well made, and and I've had absolutely no problems with it at all.
It's been dropped a handful of times with no ill effects.
I bought a second one as a gift for a friend who uses it regularly...