Q Rings

my GF's bike has biopace rings and they're horrible, feeling 'choppy' (stupid description, but the uneven feel when pedalling is best summed up this way) though the pedal stroke. Bizarrely she doesn't notice it, but to me they're weird and of no real benefit.

might be obvious but check the little notch on the inside of the chainring is installed so it's hidden by the crank.

got a biopace triple and when i got it i didn't notice the little ring was rotated round so the extra 'push' was at the wrong part of the pedal stroke and it felt really odd, like you described.