I've got the following error on booting and then after login.... First while i'm booting i've got a message that says something about my graphics card ? that it doesn't support unity ? etc After i login succesfully i got some other messages. This is obviously a bug.
Also you should remove by default one effects on compiz that windows that are not responding are grayed !! This effect has bugs too because it grays windows that are active !!!! and thus frozing them without a reason. I tried to disable this effect and everything is fine.
It gives me the sense that i'm using an alpha version i can't believe how disoriented canonical is. At least we have the ubuntu derivatives, xubuntu lubuntu etc i'm only using them right know.