A few years ago the same Sweetwater salesman would have been talking you into Tannoys or ADAMs. But Tannoys are no longer cool and Sweetwater had a falling-out with ADAM (the owner of the company used to pose in front of his ADAM S3s in his own home studio for the catalog) and don't carry the line anymore.
Even at a class outfit such as Sweetwater, salespeoples' recommendations are based on margins, manufacturer incentives and overstocks. This particular model is a fairly new product, so I'm sure the sales force is being strongly encouraged to move them, probably because Harmon is offering high-margin incentives to get the launch off to a strong start.
But that doesn't mean they won't do a great job. I like JBL gear, and you're right about 8" woofers helping to get the bass right.