550/580 EX vs. Qflash T4D?

[DocFrankenstein]

I was just looking for a flash and IMO parabolic reflector is better.

When would you buy the EX flash?
When would you buy the Qflash?

[jvmurray]

I own both the 550EX and the T4D. I shoot with the 1Ds and G5. I use the 550 only when shooting with the G5. Results are very good. I never use the 550 with my 1Ds because results are inconsistent. I use the Q-flash with the 1Ds. What an incredible combination! The T4d is awesome. I use it for events (including weddings). Results are always predictable and outstanding.

[DocFrankenstein]

Excellent. Now I only need a thousand bucks for the flash :D