It is not only the absolute pressure (aka cabin altitude, an altitude at which the standard ambient pressure is the same as in the cabin) that counts, but the rate of change as well.
As other have said, the cabin altitude in typical non-pressurised GA airplanes will often be more favourable than in airliners, by the virtue of flying lower. But the cabin climb rate, and especially the descent rate (which we tolerate worse), can be much higher.
The pressurisation systems are typically programmed such that the cabin altitude rates didn't exceed ±500 fpm in normal operation, regardless of what the aircraft is doing. That is, even if the aircraft descends at -2000 fpm, the cabin altitude will 'descend' much slower. In the end, it only needs to 'descend' from (typically) 8000 ft, rather than from the airliner's 30000 ft.
Conversely, in a non-pressurised aircraft you'll have the same rate of change as the aircraft's own climb/descent rate. Touring GA aircraft typically descend at about -500 fpm, which is gentle enough. Yet now it depends on the pilot's skill and the task at hand. A fast descent even from a low altitude may hurt.
I don't have particular problems with altitude changes, but the most painful experience I ever had was similar to what @Andrius referred to: a very fast descent (or rather dive!) after dropping parachutists from 800 m, so that we land before them. Not only my ears, my eyes felt hurt!
In other words, if you are touring and not flying over mountains (above ~8000 ft), and have a minimally experienced pilot (or learn to fly yourself), you may feel better than in an airliner. But many kinds of special airwork, or an emergency, may pose a greater problem.