How I watched it: As it came out subbed (720p), dubbed on Blu-ray (1080i)
Angel Beats is one of those series that was a blast to watch (mostly) but tried to do to much in too little time. It wants to be a comedy, action, drama, romance and even throw in some parody and music elements for good measure. It does them individually well except it doesn't have the time to develop them properly except for the comedic elements. The whole show has a rushed vibe to it and the serious moments feel out of place because of it as it brings the show to a sudden melodramatic halt, sometimes out of nowhere. If it was longer, say 24 episodes, it really could have shined but as is its merely above-average and dissapointing.
Minor quibbles over the look of the eyes, PA Works knocked this out of the park. The colours compared to other shows is almost the difference between LCD and OLED; its just bright saturated heaven. Detail and fluidtiy is stellar as well and maybe the best part is its HD native so it fully takes advantage of the picture quality enhancements blu-ray offers. From my (limited) experience with anime on blu-ray the only thing that tops Angel Beats is the Evangelion Rebuild franchaise. Not bad for a seasonal TV anime that came out in 2010.
Music- OP is download worthy but ED is somewhat forgettable sad and slow stuff thats the norm for endings it seems. OST is up to par with previous key anime, which is to say awesome.
Sub vs Dub: Both excellent, although I felt the dub was better for a relaxed funny watch (partly the casting/direction, partly no reading) the sub is the "Definitive" version that you should watch if you have no preference either way. The dramatic sequences are acted much better and the dub kinda messed up Yuri, TK and Shiina (why would you dub TK D:). Gay Nazi guy was better though so there is that.
Theres too many of them but theres only one bad one (previously mentioned gay nazi) so the lack of depth doesn't hurt that much. I'll be honest; the best characters are not the main characters nor do they have the best moments of the series. Angel Beats is at its best when its doing gags that play to the shallow and hilaurous nature of the show.
TL;DR TK FTW
The show is a near must-watch thats only hampered by a weak ending and rushed story that tried to do to much.
Blu-ray comes on 2 discs with bare minimum packaging and extras. You get the show, Dual audio + english subs, OVA (but not epilogue short) and textless OP/ED. Retial is $70 but you can find it for approx. $50. I'm a cheap bastard so I'll leave it up to you if thats worth it (I got my copy for $28 during a black friday/holiday sale).