Well, it depends on what the firmware revision is.
I've got a Creative Zen Micro, using firmware v1.x, and therefore it uses the pmp_njb.dll interface.
However, there's an option on Creative's site to upgrade the firmware to the latest v2.x revision, which then makes the player PlaysForSure compatible, and therefore it will use the pmp_p4s.dll interface instead.
I don't experience any crashes when transferring files, because my Zen is using pmp_njb, not pmp_p4s. However, CraigF (beta team & forum admin) has a Zen Micro with 2.x firmware, using pmp_p4s, and he was getting a crash every time.
WE could only reproduce the crash for PlaysForSure (P4S) devices, not for Creative NJB, iPod, ActiveSync, or generic usb devices.
5.35, coming soon, fixes the p4s device crash bug.
Creative Zen Microphoto
Scroll down to "Access Over 2 Million Songs with the Widest Range of Online Music Stores", which has a Microsoft PlaysForSure logo next to it :-)