I have experience with JDE EnterpriseOne. Your message said EnterpriseOne 8. Could you verify the version they are using. The latest version is 8.12. Also in use is 8.11, 8.10, 8.9, and 8.0.
8.0 and 8.9 have been around for awhile and are pretty much the same. It offers all the basic Maintenance functions plus a Failure Analysis Module. 8.10 includes a very nice, easy to use Equipment Costing Analysis tool plus they introduced Condition Based Maintenance. In 8.11 they added a good weekly scheduling tool. 8.12 is much better from a technical point of view, but does not offer much more than 8.11 from a maintenance functional point of view.
JDE will easily manage the basic maintenance functions (work orders, PM's, Equipment Register, Interface to Inventory and Purchasing). The system is very flexible which means it can be set up to be quite simple and easy to use, or it can end up being complex for the user. I think it really depends on how the system is configured. If you would like more information or would like to talk over the phone, please e-mail. I would be happy to help answer some of your specific questions.