Linksys is once again taking a product that normally sells for much more money (around $300), and driving it down to a price that pretty much anyone can afford. They've done a nice job with the packaging by making it stackable with their other products, and keeping the design simple and free of any controls.
The good news is that for around $80 (on-line price at time of review), the WSB24 can help improve the performance of your wireless LAN, with very little effort, and no pulling wires through walls. Since it's so easy to set up - given that you are using either Linksys' WAP11 or BEFW11S4 - you'll quickly know whether it will do the job that you want it to.
My advice is to think of the WSB24 as more of a way to improve connection reliability and throughput inside your existing wireless LAN's coverage vs. a way to expand your WLAN's coverage, and you'll be less likely to be disappointed. Pair it up with the hot 802.11b radio in an Atheros-based dual-band client card (such as Linksys' WPC51AB) though, and hoo Mama, then you'll be talkin' range expansion!