The fold up keyboards do work with the visors, I don't know why the sales guy told you otherwise.
Unless he was trying to sell you a more expensive palm. Which in that case, it'd make sense that he'd lie to you.
I have a Visor Deluxe, and it's fantastic. It'll hold 6 pages of notes no problem. With the 2mb version, if you start using AvantGo, and trying to take notes into it, you might run our of memory. When cueRadio's start shipping, I'm going to pick one up for mine. The Deluxes are ~$200 now, and if you find a staples coupon for a $200 purchase, it can be even cheaper