The original Sirens of the Sea has a mixture of excellent and insipid tracks in my opinion. I thought the chillout tracks on SotS were excellent, particularly Ashes, Miracle and I Am What I Am. The 'trancier' songs though lacked that killer passion that I now associate with Above and Beyond. It's the OceanLab style of course, but it's just not as much to my taste.
This remix album is almost the opposite - the remixes of the original trancier songs (SotS, Lonely Girl etc) are excellent, bringing together a more progressive and powerful style on some, and a housier edge with others. The most stunning remix is still the 16 Bit Lolita's Remix of On A Good Day, which can be found on Anjunadeep 1. I like remixes when they are very different to the originals, and this is one fine example.
The Above & Beyond remixes are all very good, adding that killer progression and trance club sensation that I wish the originals possessed.
However, some songs are designed to be chillout, and putting a progressive trance beat and synths on top of them ruins the original purpose of the song in my opinion. None of the remixes are bad, but when you come to love the originals and feel their ambient intent, you don't like hearing them so different.
The best exception to this is Michael Cassette's remix of Miracle, which is more housey and very upbeat, and ruins the original less than some others.
Of course, it's a good album, and as I've said before, since Anjunabeats 6, I've been harsher on all trance/house etc albums because of the superiority of that one: this is still worth the purchase.
If you combined the best tracks on this album with the best on the original, you'd have the most awesome album in the world!