External Battery Pack for a Canon flashes

Tired of long recycle times for my flash, I'm seriously considering an external battery pack to use with both my 580 EXII and my Canon MR-14EX ring flash. What do folks like/recommend?

The most powerful portable option seems to be the Quantum Turbo SC battery pack. However I'm concerned by this report of a Quantum battery pack frying two flashes, and Quantum denying blame. Has this happened to anybody else?

If I use the official Canon CP-E4 external pack, or one of the others based on AAs instead of a special battery, what sort of recycle time do I get? And how often do I have to swap/recharge batteries?

I've used Quantum battery packs for my flashes since the 1980's and have had two flashes quit working while using their battery packs. In both cases I returned the flashes and battery packs and the flash was repaired/replaced and the battery pack repaired and updated. There service and staff was exceptional. I don't work for Quantum now or at anytime in the past, just a very satisfied customer.

This is what I use:


Canon CP-E4 Compact Battery Pack

The CP-E4 gets my vote - happy with mine.