MAN has OW flights direct to DOH (QR) and HKG (CX). I don't fly to the US any more but there used to be flights to PHL (AA) and via Dublin (EI).
Short haul is bad as you need to pay as much to get to LHR as you do to get to anywhere else in Europe from LHR.
It works well SH for BAH to get a good haul of TPs but not so great for reward travel.
For long haul the MAN-LHR is free on redemptions.