On Linux (the opensuse-kde-friendly fork, running on Arch though), I cannot say I've found 29 that different. The tabs are more rounded, yes, but other than that, the difference is quite minimal. Instead of having a menu link on the left of the tabs, it's on the right of the location/search bars - I pretty much never use it anyway, so I don't really care.
On Windows 7 it is distracting, but I never liked the Aero transparency anyway. But on KDE, a non-issue personally. If Firebug works better, I'm all for it.