Over the last 3 years I've acquired a few - all torches. My original P7 SSC was great, and I still have it, but I've replaced it with a C8 XML U3 which is usefully bright on MID mode for 2+ hours, and very bright on high power.
I've now just ordered a 501b XM-L2 to uprate my lid light... at the moment I have a couple of 501b XML-T6s which have also been excellent.
My experience with the previous generation 501b XPGs was less good - one packed up (replaced the drop-in with an XML) but the other is just a general use torch as it gets too hot and then won't switch modes.
These torches are cheap as chips... my C8 XML-U3 was £15 and my new 501b XM-L2 is £10. I find that the 501b's often have heat management issues - fixed by wrapping the drop in with foil to improve thermal conductivity. They also have issues with cells rattling around inside - which breaks the contact causing the mode to switch just you are hitting something rough! But that can be fixed by wrapping the cells in electrical tape to make them fit more snugly, and by using one or two rare-earth magnets on the -ve end of the cell to make it a bit longer so it has more pressure on the contact spring (I'm using reclaimed laptop cells which are unprotected and so a bit shorter than protected 19650s).
The latest kit is unbeatable at the price... but some fettling is required to make it reliable.