Boom Burger - Rochelle Park
This place got dissed pretty badly on another board and a couple of blogs-- basically the LaFrieda wholesaler will custom make a grind for you, it doesn't assure a great burger. The place is very frenetic and is apparently appealing to the mid-20s crowd.
If you want a great LaFrieda burger in this area, stick to BuCu in Paramus.
No, they are not related -- not from what I know. The owner of Boom Burger in Rochelle Park, and his family, own several places in Bergen County (diner, restaurant, bar/night-club; in Englewood, Fort Lee, Mahwah, Teaneck, etc.).
There is also a place with a similar name in the Hamptons, but that is not affiliated either from what I gather.
The second Boom Burger location opened up in Mahwah.