Actually, the official PM cycle for the 3035 is 400K while the 4035(3530) and 5035(4030) are 500K. However, "everyone" does the 3035(2530) at 500K since everything about the three models is identical including the PM kit. The 4530 and 5530 PM cycle is 400K.
The really nice thing is that the PM kits for the 3035-5035 consist of modules (throw away) that you just swap out. They are guaranteed for the life of the PM. At first, Kyocera was very liberal with this warranty but lately they've been tightening up a bit (but not unfairly).
The only real problem with this series has been with lines developing because the charge corona and grid get dirty after around 100-200K prints. The end user is supposed to clean them with a tool that comes with the toner, but as the toner cartridge last about 50K, many people forget. Also, they often run up to 200K or more without a service call so techs aren't getting a chance to clean them if the end user doesn't. Occasionally this problem can lead to drum damage which now isn't being covered by the warranty since it can be prevented by proper cleaning. Imagine that the only thing close to a "common" problem is caused by the fact that the machine runs so well a tech doesn't see it often enouogh.
The assemblies for PM's for the 4530 and 5530 are available at a reduced price from Kyocera and these are designed to be rebuilt with parts up to 7 times. These assemblies (not the replaceable PM items in them) are guaranteed for the 2.8M prints. Again, thier idea is that you would use the assemblies (which in this case are rebuilt in the shop).
As you may have guessed, I'm really pleased with these products. We took on the Kyocera Mita line after they bought out Mita and only handle the "new" products since the aquisition.
Cheers!