I have the bead necklace (the regular one, 18.25" with 10mm beads, non-graduated) on my long-term wish list. I'd like to wear it to my PhD graduation ceremony. I think it's a great modern alternative to the traditional string of pearls, and will really stand the test of time. Like ehy210, I have a pair of non-designer SS bead studs that have treated me just fine, and I'm not so terrified to lose. I certainly wouldn't turn my nose up at a gifted pair of Tiffany bead studs, though!
As far as paying more for Tiffany, I think of it as getting the piece as well as a lifetime of service. If you buy something similar from a department store, you will be paying premium at a jeweller for every little thing that goes wrong, polishing cloths, and a full replacement if the silver tarnishes or stains badly. With Tiffany, there is apparently a cleaning charge, but I've never been asked to pay that. They have always serviced items of mine and my friends' for free, and stand by their products for the lifetime of the item. Plus, if you get sick of something, you can generally sell it for not much less than you paid...which isn't true for non-branded items. I think that's worth the extra cost!