I'm definitely going to have to try the 400's this season to see what all the buzz is about. I've been in the luxury suites at least a dozen times, and while they are great for eating, drinking and schmoozing...it's honestly one of the worst places to watch the game from imo.
When I was i NY in March I bought some tickets of ticketcity and ended up on 104 D with my GF. Was damn good seat for a virgin trip to the MSG.
Started having a chat with the guy sitting next to me. He told me that he usually had other seats on his season ticket and that the tickets for that night (vs. Buffalo) was his birthday gift from his wife/family...
I always try to get tickets in that section off stubhub.
From my experience, a lot of good people in the section, funny people, and it's close to concessions that are inside the bowl, without having to go into the hall way.
It's kind of like a hang out up there. And it's a center ice view.
My father's seasons are in the first row of 405 and I have to say I don't think there's a better value in the arena. I know everyone around us, as you said the concession stands right there so you could get something quick and not miss a thing and 404 tends to be rowdy so it always creates for an interesting atmosphere up there.