In all fairness, I must admit that we've come across dimmable twist bulbs before that were not up to scratch. It's proving difficult for companies to produce a bulb that will last a long time--like the other CFL bulbs do. As the years have passed, things have improved nicely, to the point that we are comfortable offering over 40 different models of dimmable CFL's.
Since these bulbs cost more than standard ones do, it's tempting to just use regular bulbs in the dimmable fixtures. Since this will lead to the demise of the standard bulb within weeks, if not days or hours, I do not recommend this route! =)
I also don't recommend settling for an off-brand bulb, especially with dimmables. This techonology is complex and newly improved, so make sure you get a brand that is trustworthy.
Take a look at our dimmable fluorescent light bulb selection to see if any of them fit your needs.