I too use the pendraken/kallistra range, those siege towers are very good value as are the bombards, mantlets and rams.
But donnington minis, fills the gap there is in the market for the reamining equipment you need.
Old glory stuff is expensive compared to these and whenever I ask to see the stuff at shows, they always give the impression they cannot be bothered so I have always returned the favour.

Now if only we had a comprehensive set of siege rules including rules for mangonels and scorpions we may be on to a winner
