Sorry for the delay in responding ...
I like the B-8 for nostalgic reasons, but I prefer the newer style, like the Model S105A to which you linked, because of these features:
1) plastic dispense trigger (versus the pull string on the B-8)
2) more durable shampoo dispenser that stands better than the B-8's when filling
3) it's heavier than the B-8 due to the cord winder, so it grips the carpet better; the caveat being that it can be hard on the back if doing a lot of shampooing at one time
4) the sudser shield's fastener is more durable than B-8's
5) nap lifters (not meant to be used with the B-8 according to Electrolux Corp. literature—even though they kind of fit—due to eventual motor and spindle damage; a good number of Aerus rep's don't know this, or they just want to make a fast buck by selling more nap lifters)
6) automatic cord winder
7) optional drip tray clips allow easy, drip-free carrying (albeit they may fit onto the B-8's drip tray, too)
8) the shampoo tube does not need to be removed with the shampoo dispenser when emptying or refilling