How Omportant is PS-RIP?

I looking to replace an aging printer that is balking at heavy card stock.
I've narrowed my selection to three printers. Two are variations of the same
model, with the tradeoff being duplex included vs PostScript RIP. I do
duplex printing, so I can weigh the importance of that, but I don't have the
capability of using RIP with my present printer, so I have no idea of it's
value.

The printer will be used for mid level to high level graphics projects,
printing photos and some general color printing. I do need the large paper
capability of these printers, so a lot of other choices have been ruled out.
I already have an excellent quality B&W laser printer, so I'm not
considering a color laser printer.

Can someone give an idea if it's something to consider? BTW, I can add a
duplex option to the model that does PS-RIP, . The two models are in the HP
9600 series and I'd also like to hear if anyone has any experience with that
line.

The other printer under consideration is the Epson 2200. There's quite a
difference in price in price between the Epson and the HP printers. Does
anyone have any comparison experience with these two lines? I use HP laser
printers, but I've never used the high end HP inkjet printers. I've been a
big fan of Epson inkjets and the printer being replaced is an Epson 1520. It
has given good service over a relatively long period, but it needs to be
replaced. Any help comparing these two lines would be appreciated.

Thanks!