I got a 5060 in 2011 and have about 250 hours on it. It has been very reliable. I have the 23 hp Kawasaki motor, which I can say is very strong.
It cuts very nice and even, even when the blades aren't super sharp. It throws clippings about 10-15 feet out the side. It can clump, like any other mower, if you let the grass get too long or cut it wet.
The battery died after 5 years, which is not bad. It has had no other service issues, except those created by me. Grass can accumulate under the cowl, and that can limit airflow and cause overheat issues, so clean it out occasionally. It doesn't say to do this in the maintenance section of the manual, but it's very important to do.
On both my mower and my neighbor's (both 5060), it does not drive 100% evenly on both sides, especially in reverse. I think it can be adjusted, but I never found it to be too annoying.