No direct experience, but looking at the specifications I don't see why it won't print good negatives.
The ink set is very similar to that of the P800/900 so it should have good density in the UV. Curves designed for the P800/P900 printers may need a little tweaking but I doubt they will be far off.
The vacuum mechanism for paper handling should also be a large plus with regard to printing on OHP film vis-a'-vis "pizza wheel" issues.
Since the P5470 is a pro level printer you should expect a much higher level of service from Epson than one gets with the typical printers. This includes both pre-purchase service from the sales department as well as post-sale service.
Thus, I would get in touch with a full-service Epson pro dealer and see if you can arrange for a custom demo specifically regarding printing digital negatives. At the very least, they should be willing to print a few files for you especially if are willing to send them the media. An in-person demo would, of course, be preferable.
My $0.02 worth... hope it is useful to you.