Well its completely possible you had a bad tech. There is such a mixed bag of them. A good one will do their job, know everything, and test everything properly, etc...
Others make assumptions and are lazy..
Him recomending the hitron... eh.. yes/no.
The new hitron, is a dual band wireless.. much like i mentioned above.
Do you HAVE to get their dual band gateway and spend more? No.
You could get a 3rd party one just as easily (and might work better still).
http://www.canadacomputers.com/product_info.php?cPath=27_1046_1047&item_id=044938
(you can buy it anywhere.. i am just posting one stores page for it)
This is probably one of the BEST reviewed dual band routers out there... likely my next replacement router when i descide to swap mine. (currently linksys e2500 dual band)