I believe the Scorpion & similar bulbs are rated for about 2-3 battery changes. SureFires are not officially rated (this has been discussed before), but you should get about 15-30 hours from your SureFires (this depends so much on useage characteristics and is difficult to nail down. If a bulb lasts 5-10 sets, it will usually last double that...
I use my E2e about a set of SF123As a week, and never had to replace the bulb. I had one N2, and one N62 lamp die of old age after more battery changes then I could remember.
Bulblife of SureFires is not an issue I would get even slightly worried about.
As posted before, Surefire will warranty their bulbs for 20 hours. This has been stated to me by customer service at Surefire. Three times I've had to have lamp assemblies replaced and my word was never questioned by Surefire, nor asked that the blown LA be returned for verification.
The issue of whether Surefires are too expensive is subjective and has been discussed in this forum many times but their customer service and the resolving of problems has generally been held in high favor by posters of this forum.
Well yeah, I have stepped off my soapbox and now I don't think they're too bad as long as you can find a decent source of 123s. The website needs to be rewritten though, it says the estimated battery life by all the bulbs but that can easily be confused, as I did, with bulb life. It says
"15 lumens for 75 minutes"
Now isn't that just plain confusing? See, what would I have done without CPF?