I might as well add the link to the 3.55 debug firmware (I've tested this on one of my Test/Debug Units and it indeed does work.). [Register or Login to view links]. This isn't my link so I don't deserve the credit.
I read in your previous posts you have or had a debug unit from day one, so I take it you have tried and tested this firmware?
I have played with rebug on 3.55 but not the odbfw, do you know what the differences are between the two?
In short a debug unit is for testing/debugging unreleased games. ODBFW will allow you to play retail discs, but they will now allow you to decrypt retail PSN pkg files. The store for the debug isn't user friendly at all. In fact you will have lots of trouble finding debug PSN software.
Debug Firmware will allow you to shut off HDCP and allows downgrading. Rebug will not that I'm aware of. These are the only real advantages a debug has at the moment over rebug.
Debug Firmware allows you to debug software using ProDG. Also an advantage over rebug assuming you know how to debug. Debug Firmware doesn't allow backup managers to work but you can use the official BDEMU if you have the software and you are limited to 4 disc images with the official software instead of the unlimited by the backup manager.
Debug Firmware doesn't allow Blu-Ray movie playback. Rebug obviously does.