How about native OS user interface?
Yes the UI is slow on my old laptop(AMD Turion 64 X2 Mobile@2000MHz; ATI Radeon X1250) and that is the biggest issue so far.
Still, i like where all this is heading and maybe i'll finally have a real alternative to the old opera(which i'm still using)…
ps. The panel toggle could've been thinner(2px max)