I swear by the Osrams. Got a pair in my Eunos (a car known for poor lights) and combined with some Raybrig crystal lenses they are nearly as good as the OEM Xenons in my BMW, been in the mazda for 12months so far...
My wife's car also had some 100w blue bulbs in it when we got it, I fitted the Osrams and even she said the difference was night and day, this was nearly 2 years ago.
There are quite a few tests out there, and the Osrams are always up there, best VFM IMO.
Did you touch / contaminate the glass on the bulb when fitting, as this will also shorten their life.
What If There Were No Hypothetical Questions?