I'm thinking about getting a SureFire 6PX. I haven't really seen much of SureFire's current lineup, the last SureFire I had was an original 6P LED, the 80 lumen model. I'm wondering how the current lineup (e.g. the 6PX) compares in terms of build quality. I understand the head can't be removed for an upgrade anymore... other than that, anything I need to be aware of? Are they still as solid as they used to be?