I currently use it. I don't know anything about the progress, but it is unfinished, it is very playable though.
if nothing else, it is an awesome download just for all the morrowind armor and weapons it adds which are all placed in one testcell for easy access(in addition to across the SoVvM worldspace). I use these more then the world space, actually.
there are tons of mods out providing Morrowind armor, weapons, books, ingredients,drinks etc etc....like for example Vardenfall exports and cobl
I know Onra's using the SoVvM heightmap as a reference for his own, but I think the original SoVvM mod is in its own worldspace. It wouldn't be incompatible with Onra's, but you wouldn't be able to sail around it like you can the rest of Onra's work. When Onra releases his Morrowind heightmap, it WILL be in the Tamriel worldspace.
yeah I have placed Vardenfall and Solstheim in the Tamriel WS already....creating regions for it similiar to the SoVvM regions should not be a big problem ( btw ...AmpolX has created an amazing looking Bittercoast region which will be probably used for it ...if he is still arround

)
cheers
onra