I just received my unit the other day and tested it out over the weekend. I noticed I get a 27 frame clip before each of my clips. I didn't noticed any buffering happening but quite the opposite. So I did a clock test like some suggested and found I was getting a ten second delay on the clip after the 27 frame clip. The clips showed up in the unit as well as in log and transfer.

On my Canon HX-A1, I pushed to start when second hand reached 12 and stopped at 6 (30 seconds), then started again at 9 then stopped at 12 (15 seconds).

The resulting clips:
#1- started at the 12 stopped after 1 second
#2- started at the 2 stopped at the 6 = 20 seconds
clips #1 and 2 are from the first 30 second sequence, missing 9 seconds of footage.
#3- started at the 9 stopped after 1 second
#4- started at the 11 stopped at the 12 = 5 seconds
clips #3 and 4 are from the second 15 second sequence, missing 9 seconds of footage.

I didn't do any setup just mounted the unit, plugged it in, and away I went. It works awesome otherwise, log and transfer was quick after loading the plug in. My clips were solid and clear, no dropped frames after the 10 second delay. Maybe this is what I get for going cheap on the card ($77.00 @ B&H). For the stuff I do I can deal with it as I am tired of losing key footage in my clips from dropped frames on tape. I work in a dirty environment (desert dust).
Does anybody have any suggestions? Did I not do something in setup?
Sony MRC1K Test with Kingston 32 gb 133x on Vimeo

After using these settings, all is good I only lost the last 2 seconds:

For anyone wanting to know the exact process of making it work with the A1 here it is:

So record to card only this is my process:
- In the A1's menu so "System Setup ---> DVControl ON"
- Connect the firewire cable between the A1 and the MRC1K
- Turn on the MRC1K throw in your CF card (it won't let you get to the MRC1K's menu without a card in it) and go press the MENU button
- Now go "SETTING ----> CAMLINK SEL"
- Choose "SYNCHRO"
- Now on the A1 you should see a green box next to "DVCONTROL"
- Your now able to control the recording with the A1's record buttons and don't need to shoot tape at the same time

That's all there is to it. Once it's set once you don't need to do it again. Just connect the two and turn the MRC1K and you're ready to go.
I may to a little youtube vid about it or something.

A huge thank you to the people on this site to help me figure out a tapeless solution so I don't have to upgrade and can keep using my XH-A1

http://www.vimeo.com/8534578