HRtP: Nothing too special, Eternal Shrine Maiden is one stand-out track.
SoEW: Quite a good OST, World of Empty Dreams, A Phantom's Boisterous Dance and Complete Darkness are awesome. Also worth mentioning the superior version of Master Spark.
PoDD: There's a few hits, many misses, good tracks include Reincarnation and Strawberry Crisis.
LLS: Wonderful soundtrack, one of the best in the series, Bad Apple, Lotus Love, Sleeping Terror, Dream Land, Inanimate Dream, the list goes on.
MS: Quite good, Romantic Children is great, lacks a large amount of stand-out tracks like it's prequel. A problem with MS's OST is that, using Infinite Being and Grimoire of Alice, the tracks are very very repetitive.
EoSD: This soundtrack doesn't hit me as much as it does a lot of people, my hits are Voile, the magic Library, Locked Girl and The Centennial Festival for Magical Girls.
PCB: Another great OST, the weaker stages on this are stage 2, stage 5 and extra.
IN: I don't like IN's OST, Voyage 1969 and History of the Moon are about the only good ones.
PoFV: Suffers the same fate as the other phantasmagoria, the good tracks are mainly exclusive to the new* characters. (*Swapping Aya out for Yuka) Therefore, Flower Land, Riverside View, Fate of Sixty Years and as a matter of fact in just the last week, Forsaken Doll has grown on me in the last week or so.
MoF: lol, MoF. Dark Road, Dark Side of Fate, that's it. Mostly horrible OST for a mostly horrible cast in a mostly horrible game.
SA: A brilliant increase in quality from the prequel, another stand-out OST in the series. One bad track?: Last Remote.
UFO: Hahahaha no, this is another MoF without a single good track even in the demo, hopefully TH13 will be to this what SA is to MoF.
IaMP: I don't enjoy this one too much, the shmup originals are the better ones, although Voile is great.
SWR: Same as IaMP, Legendary Fish and Tenshi's three themes are good.
StB: No.