I have the RPP trigger from when it first came out, which has similar advertised weight reduction to the Timney. It is more of a hybrid semi-curve trigger shoe vs the Timney flat OR traditional curved trigger. I don't know if anyone has done a trigger action comparison (haven't searched) but both stop the flop and have ~3-3.5lb weight.
Although both are roughly similar price points, I would argue that theoretically the Timney is better (or at the very least, better value) than RPP because it includes trigger+sear, hammer and spring that are fitted to operate together, whereas RRP doesn't include the hammer. So as a result, the sear to hammer connection is entirely YMMV. My RPP trigger+sear works perfectly with the factory hammer (it was basically a NOS JM Marlin) but that's sheer luck to achieve a crisp, light trigger pull, with the personal preference benefit of the wide serrated trigger shoe. As I understand it, Timney has a narrower, more traditional feeling shoe in both flat and curved versions.
EDIT: I didn't remember the (original) price of the RPP trigger, but it is currently $99USD (er... up to $150CAD), whereas the Timney kit seems to be $180-200 USD. Either is good value but I maintain my comment above in regards to sear-hammer engagement.