Disadvantages to high speed sync?

I have just recieved my 430ex and have been playing around with it. I really like it, especially when bounced. I also purchased a Sto-fen Omni -bounce, but bouncing the flash off of walls produces a much more pleasant result. I have also experimented with the high speed sync in the AV mode (with the flash speed set to 1/250 in the custom functions) and like this very much. My question is, are there any disadvantages to using this fast shutter speed? In program mode, the camera (30D) sets the shutter speed to 1/60, but the results are identical, even in the histogram. I appreciate any input.

High speed sync cuts in with shutter speeds above 1/250 sec. At those speed ranges the flash will emit several smaller bursts of light rather than the single all-out burst you get at or below X-sync speed. So when HSS is working you'll get less power from your flash. The manual should have a table suggesting what this reduction is. The manuals for the 550 and 580 do, anyway.

Even with HSS activated, the flash unit will just use normal flash at shutter speeds 1/250 or slower with your 30D (since 1/250 is the flash sync speed for that camera).

Any shutter speed between 1/60 and 1/250 will not likely result in different exposure indoors unless you really crank up the ISO to include some ambient light.

Here's a little info about high speed sync.

The Small Flash and Studio Lighting section might be a better place for this thread.

I was going to post a similar question last night but never got around to it. Is there any reason to not always leave the flash set for high speed sync? As Curtis stated, if your shutter speed is below the HSS limit, you'll get the normal flash anyway. But, if your shutter speed exceeds the HSS limit, the flash unit would already be setup to operate accordingly. Am I missing something here?

Apparently, I was also confused and am not using high speed sync. Let me rephrase my question. In the custom finctions of the 30D, you can set 1/250 as the default speed in AV mode. Is there any disadvantages to doing this?

The background in low light situations will be very dark, while if you don't set it you'll get a reasonably well-exposed background, toning back some of the "flash" look of the photo. Of course, that might be a well-exposed blur if the time's too long.

Thanks, Jon.