They are still one of my favourite thrash metal bands. I have all of their albums (except for "Kaleidoscope" and "Pictures At An Exhibition") and their "Toccata" maxi-single (no, that's not the famous Toccata by Bach).
My favourite albums are their eponymously-titled debut and "The Music Of Erich Zann", but I also like their newest release "Lurking Fear" very much, especially "Defenders Of The Faith" and their version of the "Allegro" from Shostakovich's symphony no. 10. The title-track of their album "Dances Of Death" is also among my faves and probably one of the longest thrash metal songs ever written - it's about 20 minutes. Actually, it consists of 8 parts and is written, as bassist and songwriter Ralph Hubert once explained, in the form of a rondo. I also like the version of Mussorgsky's "Night On A Bare Mountain" on "Dances Of Death".
I think on nearly every album is at least one piece by a classical composer, the first one being "The Hut Of Baba Yaga" on their debut. One of the reasons for the classical influences in Mekong Delta's music might be the fact that Ralph Hubert started as a classical concert guitarist (if I remember correctly). On their album "Visions Fugitives", there's also a "Suite For Group And Orchestra" mostly written by Ralph Hubert himself.
Mekong Delta's music is played on a high technical level and it has a very specific, original sound. At least I can't think of any other band which sounds similar to Mekong Delta.
But before you decide to buy an album merely based on what people are telling you here, you should also check Mekong Delta's
official website, where you can listen to songs from several of their albums.