I love SpiderLites but I don't see them as an alternative to good quality strobes. I think of them more as an addition. Buying the SpiderLites and the bulbs to use it as a strobe is not cost effective. It's nice that you can use flash bulbs but what makes the SpiderLites cool is the continuous fluorescent aspect. Those things are very good when it comes to maintaining color temperature.
A kit with Spiderlites, is expensive by comparison to studio strobes and you don't nearly have the flexibiltiy.
Having said that, I've really come to love the idea of using continuous lighting for some portraiture or for those times when you've got a 'blinker' or a child that is frightened by the pops of the flash. Using Spiderlites in conjunction with natural window lighting is also quite nice but in a studio environment using just SpiderLites, you'll have to crank the ISO to about 400 and drop your shutter speeds to about 1/60 or 1/80, as well as using larger apertures. None of that is a bad thing and many do it quite well but these are things to be aware of when you're planning and thinking of continuous fluorescent.
The late, great Monte Zucker used Westcott (I believe it was an endorsement) SpiderLites and softboxes and created beautiful portraits.