My two cents. I have a lot of respect for both groups. I am currently running TW version but will be flashing a eugene kernel over it once things settle some.
Why did I pick the TW you may ask. For me it is simple. TW is a base of just samsung files for the vibrant. Flawed or not they are all kinda matched. Both roms are WIP and will be for some time but as more devs pick up on the roms they will likely use the vibrant base. That said Eugene has a HUGE HUGE advantage in the kernel department as he has been working with them for months.
So for me the TW base and work with eugenes custom roms till someone else starts modding kernels for 2.2
TW = Team Whiskey... not Touch-Wiz