UVC bulb question

[ScienceRulez]

I've been looking around for a while trying to find out if there is a quality difference between the "cheap" and more expensive UVC bulbs that I see for sale. Most of what I find is sales literature basically saying "Buy our bulbs because everybody else's are trash." So has anybody else noticed a difference, or is there any difference?

Disclosure: I'm asking because a canister filter has a built in 9w "sterilizer". I have been using it on my freshwater tank for algae control.