Announcers were by no means great, but you have to compare them to the rest of the announcing crews right now doing NFL games... and when doing such, they're probably above average, or at least average.
On the other hand, that was the first NFLN broadcast I've watched, and I was very disappointed with the overall presentation. Every single timeout, kick, or whatever other stoppage there was... they immediately went to a commercial. WAY too many commercials that game. Stop and offer some insight on timeouts and kicks. Money hungry bastards need all their commercials. And then the "analysts" they had beforehand and at halftime... total crap. Marshall Faulk is a complete idot, PrimeTime blows, and Mooch is average at best. They did a bad job of advertising the station on their first national telecast, that's for sure.