Sigur Ros a truly amazing album. Not one song on there that I'd feel I had to skip when listening to it. Fantastic.

For me there are several things that make this a great album, firstly, the way it flows effortlessly from songs to song which is a rare quality nowadays. Secondly, since the album came out every song on the album has been my favourite at some point, i can only say the same for albums such as Dark Side of the Moon and the Bends to put this into perspective.
In comparison to their previous work it is far less blusey and a lot more experimental with sounds they use. I prefer this album as a whole but my favourite tracks they've done are on Agaetis Byrjun.
As to the use of Hopelandic instead of lyrics i find it works wonderfully. The songs focus on a many layers of different riffs and melodies and the vocals are primarily a part of the soundscape. I can't speak Icelandic though so it makes no difference to me whether they sing in Iceland or Hopelandic.

Their self invented language only made from vowels is just a bad excuse for not writing real lyrics - but it is better without lyrics in the monotony.

However it is nice of them to release stuff for free on the internet.

I recomend that you support them and buy the record.