Having 35 items of Aristo-Craft stock and 15 Bachmann Big Hauler stock caused me to standardize on Aristo-Craft couplers. I liked the Bachmann coupler - looks more prototypical, but does develop a weakness after some time. This allows premature uncoupling whilst trains are in motion. :timeout:
The Aristo couplers work well and of course are usually readily available from UK dealers. The only occasion where slight 'surgery' and shimming was necessary was upon two Bachmann 'Annie' front pilots. Not a difficult job however taking only around five minutes per loco.