I have tried out all the brands I can get my hands on.
SureFire SF123A batteries are the best. I've now tested side-by-side, SF123As and DL123A Ultras, using P60, P61, N2 and MN16 Lamps.
SF123As give you a brighter whiter output for longer.
Try them for yourself.
If you find a brand that beats them, I'll try 'em out cos I get through hundreds!
Al