From a purely qualitative experience, the readers on YRT seem to be reading cards at a normal pace compared to when they first rolled out. But there still is a problem of readers not reading cards or having extreme delays to the point that the driver tells passengers to tap on their unit. At the same time I did try out an experiment with two different presto cards both with loaded monthly passes. My first generation card (green) gets read lickety-split and rarely has a delay. My other card is a DC Comic Presto Card, definitely has on more than a few occasions experienced delays. Cards tapped on the driver units don't seem to have any problems, though I'm not for sure as it's rare to tap on their unit.
The passenger units on the buses experience the most problems from what I experience.