Mine is a pre-war Denbeigh power hacksaw, flat belt and all. Had it since the late 80's. Weighs a ton, done a LOT of work, never ever had a problem with it. Bit like a shaper, it drinks oil. Pick 'em up in decent nick for a couple of hundred quid, and will outlast you.
The trick to getting them to cut well, is
a) correct tpi blade for the material
b) make sure the hydraulics are working well, so the blade is lifting on it's return stroke.
Then get on with something else or go make your cup of tea…
Me being a luddite, i love 'em.