I'm using the Sharp ROM, because it is, I believe, the only completely working ROM currently (I may be wrong about that, but I think that's the current state).
I use the 6000 for work, in a Windows environment (sigh), so I also need the ability to sync to Outlook (sigh).
I also think tinyrooster is not telling the whole story: IIRC, the 6000 actually is potentially faster than the other devices, but it's the software that's slowing it down. Guylhelm has a faster kernel that speeds things up, and the 6000 has the potential for accelerated graphics that are not yet explored.
Have fun...get familiar with the things you want to do with your 6000, then explore.