Object::Tiny is. Tiny that is :-) It only generates read-only accessors, but the interface is *far* cleaner than Class:Accessor:Fast, it's easy to override and is just absolutely yummy.
It's better than Class::Accessor::Fast because:
* perltidy and text editors (and me) loathe the extra curly to use a hashref for object creation as it takes two extra lines and an extra level of indentation. The data has to be copied anyway, so Object::Tiny's constructor is no slower than CAF
* mk_ro_accessors syntax is ugly
* Profiling with NYTProf shows the accessor properly (eg Object::id vs Class::Accessor::Fast::__ANON__[Class/Accessor/Fast.pm:52] )
* All those extra entries in the symbol table from CAF upset me.