Would have to agree that the Creo rips handle VDP jobs better than any other rip on the market - for any printer supplier!
However I am surprised that the Fiery is taking so long on these jobs. Perhaps it has something to do with the way the VDP jobs are being created? I'm more familiar with PSMail for the Mac than for PC - shame that Objective Lune seem to have abandoned the Mac version - PSMail was a Mac program long before it ever appeared on a PC when Atlas were making it.
Some things to remember…
If you have any variable text, try to get it in as small a text box as you can. If you put variable text in a big text block then the whole text block becomes variable so cacheing won't help ripping performnace.
In PS mail if you can set the background colour of any element to white instead of the default transparent, then the program doesn't have to workout if any object are to be visible or not - obviously you can only do this if the background to these objects is white.
Make sure you check any/every option that mentions using the rips cacheing ability - I've seen even properly designed jobs (on a Creo no less)
take 3-4 hours to rip around 300 records with cacheing not enabled - turning on cacheing and the entire 20,000 record job ripped within 10 minutes
I'm fairly certain that the later Fiery rips handle VPS as well as PPML, both of which should give better ripping performance than optimised PostScript. I don't think their VPS implementation is as good as Creos however - VPS is a Creo invention after all