During initial construction stages of project,
we performed air leakage testing at a small sample of apartment units at intermediate stages of scope to assess success of implementation and help the contractor understand air sealing measures.
I totally agree that a poorly designed hydronic system will
perform badly, but equally well - designed hydronic and forced
air systems will not
perform the same... it seems to me to be a matter simply of surface area and
leakage losses, both of which will be less in hydronic systems.