I would not advocate this use for anything other than those applications that require the performance or memory gains or both.

Didn't think you were :-)

Blanket statements that all Perl OO modules should be hash-based completely ignores the possibilities of 3 or more other ways Perl's flexibility can be used to good affect to avoid having to drop into the nightmare of XS programming or the deep dependancies of Inline::C.

Agree completely.

The only issue I had was with "little extra effort and no loss of clarity" since I think array based objects end up involving quite a bit of extra work in many real world situations. The final working code can look quite clear - but getting there, and later maintenance, can be a complete bugger.