This is where I get them:
http://www.replacementlightbulbs.com/lampefp.htmlIt pays to remember that the code "EFP" is a standard and this means that all the lamps that meet that standard will basically perform the same way. Maybe "better" ones will exceed minimum specs and get under maximums by more than cheapies, but you're not getting 150 hours out of a 50 hour rated bulb no matter who makes it.
Basically whatever lamps I've ever used: I put 'em in, they light the screen up pretty much the same and one day long after I've forgotten how long they've been in there, I go to show a film and the screen stays dark.
Then I have this little mantra I say to myself:
"please be the lamp!, please be the lamp!, please be the lamp!..."
Then again since lamps are probably among the least expenses I have doing this hobby, I buy the Osrams because they have the best reputation. (It's kind of like filling your tank with premium gas even if you can't feel a difference!)