Aw man, I love how everyone who has a complaint about the pricing/timing/etc. of the map pack are either whiners, trolls, or (apparently) too poor to afford the pack.
I'm gonna have to agree with everyone who thinks this is super overpriced/early. I love Reach, and have put many hours into it playing with my friends, but after playing all the maps many times, I gotta say they really screwed the pooch with the Reach maps. If all the maps weren't ripped straight from campaign, I wouldn't feel so ripped off. But I'm seriously feeling that they just got lazy with making maps, and said "-blam!- it, if we just give em' campaign maps now, we can charge em' for real ones later."
And like Halo 3's first map pack, I have a feeling that at least 2 of those maps will be fairly awful (Rat's Nest and Foundry, anyone?).
400 points I could stomach, but 800 points is really, really steep for something that I feel should have shipped with the original game (not these specific maps, but just more non-campaign MP maps).