Dont take this the wrong way mate but I'm puzzled by your statement,
Reliability: XML would be more reliable than a Q5 because it is newer technology, and runs cooler.
Runtime: obvious that an XML will give you a longer runtime than the Q5 as its more efficient.
Beam pattern: XML will give a better quality beam (flood with some throw) V's Q5.
Yes Q5 might throw further, but I never said I wanted it for a thrower.
And yes I understand that we don't have to rush out and buy the latest and greatest led light if the one we have does the job - but this is why we are flashaholics, if you could buy two of the same lights for the same price but one has a narrower beam @ 130 lumens and one with a smoother beam with longer runtimes and 600 lumens (on tap if you needed them) which would you choose?
Btw this light came out in 2008, that's why they have a Q5.
Newer LEDs are not necessarily more reliable. In fact, the XP-E or XR-E (Use the part number, not the brightness bin) has been run in countless applications for tens of thousands of hours of real use and abuse. Some time ago a well-known LED maker flopped on a new release - big press, big numbers (For the time), and a horrendous failure rate once it hit the markets. The XM-L probably won't do this, but the XP-E is a known quantity.
Flashlight design isn't putting the newest things in a tube and selling it - it's a balance of cost per unit, optic source size, optic size, battery choice, unit size, interface, control type, and so on. Polarion makes SAR gear, which usually wants throw - to see through mist, fog, and smoke. Anyone can get the aftermarket diffuser (Which I assume exists for this, but haven't checked) for a floodier light. If Polarion chose a throwier beam for a small light, they're forced to use a smaller-die LED, like the XR-E or XP-E. An aspheric might give a tight throw, but just ask Saabluster what it would cost to put quality aspherics into production - and the tradeoffs involved in it (Patents alone...).
I don't mind rough beams if it shows me what I want. My SC600 has to crank up to 750 lumens (XM-L, Runs an hour and a half, boiling hot) to see the fence, while my mag lite does it at 70 lumens (XP-E, Runs 10 hours).