Well, I think netProphET has good points (btw, nice testimony

) , but this has been discussed and Ryan has already clearly stated Tattoo was not going to be changed.
Remember though that MODx will remain the "mainstream" branch (i.e not requiring php5.1+, which is still costy for personnal use), while Tattoo will target the higher end of professionnals (and possibly, if I am not mistaken, the ECM segment).
All in all, branding is a definite plus but as Poggle puts it, the product merits is the core success factor. Personnally, I like the provocative touch of Tattoo, but also the idea of leaving a mark is ambitious and I like it a lot ! All in all, I am not sure one can predict how a brand will be perceived, despite all the $$$ put by companies into marketing studies. I am the kind of guy who believes that a vision is more powerful than any marketing study and numbers.
Tattoo certainly embodies a vision of what web applications should be like in the future, and that’s one reason that I joined the adventure : not only the application itself, but the vision behind it.