Some of it is really of no interest, some of it isn't. With "American Dad" out on TV with many episodes shown, the segment of the DVD that gives you insight into that show is really obsolete. I suppose some of the interviews might be interesing for looking for more insight on Seth MacFarlane, or for those who have never seen the man behind the show. The interview about Family Guy Season 4 is interesting in retrospect, I suppose.
The restored "Road To Rhode Island" doesn't really make it worth it. It's just the one deleted segment, and it really isn't funny. I notice the first review says "true fans have to have this scene," frankly, I think that's ridiculous and pedantic. If by "true" fans, you mean insanely obsessed, then I guess you'd be correct. It's not really offensive, but it doesn't add anything to the episode (which is a good one).
Now, it sounds like my review is completely negative. Why is this worth it?
Well, let me be honest. I love the commentaries on Futurama. I think they're among the best commentaries I've ever heard, and they just add to the rewatch value of the episodes. But a lot of Family Guy commentaries have been... just... blah. Maybe it's because they choose mediocre episodes to do commentaries on "Ready, Willing, and Disabled," "Death Lives," "Holy Crap," etc. But the commentaries on here really make this DVD worth it, I think. The commentary for "Rhode To Road Island" - I like it, it's great, it's hilarious, you should hear it. It's already one of my favorite episodes, this just made it better. The "To Love and Die In Dixie" commentary was okay, nothing special. But two episodes I'd always wished they had done commentaries on but didn't - "I Am Peter, Hear Me Roar" and "Lethal Weapons" - they finally did here! Excellent! In particular I thought the "I Am Peter, Hear Me Roar" commentary was one of the best they've done. There's nothing new with the "When You Wish Upon A Weinstein" from the Season 3 DVD.
In conclusion, the new commentaries make it worth your while to check this DVD out. As for plunking down the money, I could see Family Guy fanatics doing that, easily, I'm not so sure the casual fan will think this is worth the investment. It's definitely worth a video store rental though, absolutely.