One thing we must not forget that these are bulbs not company fitted HID / Bi-Xeon Lamps. So, keep your expectation bit low. Yes, they work quite better than stock bulbs.Yes, the are lot better than Philips Xtreme. But they don't do any magic. The don't turn the night into day.
I cannot comment on life as I am a new user. But I got another pair as backup. I have experience of Philips Xtreme. When I first installed them, a bulb got fused after 6 months. I installed second pair in September 2012 and that is still going strong. I installed another pair in my second City and a bulb fused after an year. Now, I have installed PIAA Xtreme. Let see how long it lasts.