A reader is already reporting a problem with the new 5.04A driver for the Epson Stylus 800. He writes that, with background printing enabled, he got a Type 10 crash after printing from a program, quitting the program and then relaunching it. The culprit is the Epson Print Monitor 3 file. Kurt Wiley reported a similar problem with the Print Monitor file, but also implicated Power FPU 1.2.
Update: Michael Simmons deatils a related bug: "When using background printing with the new Epson Monitor 3, if youhighlight/select the current print job, then click on the Trash can, the computer will freeze. It happens everytime." Aside from that, he was impressed with how fast and "rock-solid" the new driver is, especially as compared to previous drivers.
Other web sites (including the MRP and MacInTouch) reported a problem with the paper size default (it defaults to A4) of the Epson Stylus 600 3.2AE driver. A replacement driver (3.2AA) has now been released. However, Corky Brown says he still has the A4 page size problem with it.