My understanding, tho I haven't been in awhile and this could've changed, is that there is no hostess, no waitstaff...it's just Carlson and the other dude (partner? sous-chef?). They have a VERY small number of tables, and a HUGE demand for reservations... these two things put together are why it's so hard to get through... I imagine with the sheer volume of calls they get, a night fills up fast, and they don't call back if there's nothing available.
Tip: If you can be flexible, your best bet is to call and leave a voicemail saying you'll take a reservation whenever they have one. That will generally get you a call back.
And yep. food's THAT good!