I voted for Edge Of Sanity, one of my fave bands.. I also like Nightingale a lot ( listen to nothing but Nightingale nowadays) and stuff.. The man is a genius..

Haven't heard Moontower yet, but Pan.Thy.Monium (and the even crazier Tintin-infused Karaboudjan) will probably get my vote anyway. Dawn Of Dreams and Khaooos & Kon-Fus-Ion blow 95% of the world's music out of the water.

I think Steel has to be honourably mentioned for the fun, ridiculous cheese factor:

Nightingale
Moontower
and the two Crimsons albums

These are the only things I've been listening and enjoyed. So I can't vote.

I feel like posting videos
Pan.Thy.Monium's best song IMO:

And (not in the poll) Karaboudjan:

Edge of Sanity, it is an extremely underrated act, coming out with classics like Purgatory Afterglow and Crimson. I like Bloodbath, good ole' traditional death metal, but the more progressive band always wins for me.

Hail Of Bullets.

I'm a big Ribspreader fan myself.

So dirty, So good.

Pan.thy.monium will always be my favorite!

I made a pan.thy.monium play through along with guitar tab to the song IV from dream II, if anyone is interested. It’s extremely hard to find tablatures for this band, so I thought I would share.
I hope this is allowed, because Pan.Thy.monium needs to be more known.
Guitar Proof 20: PAN.THY.MONIUM - DREAM II - IV Guitar Lesson & Tablature Death Metal
https://youtu.be/Vupq4R2l5oE

Nightingale by far.
This is an old poll i guess because Witherscape is not there. That's a great project IMO.

My order would be:
1. Edge of Sanity - Crimson is one of four albums I would consider to be a perfect 10/10
2. Bloodbath - Nightmares Made Flesh (9.5/10) is my favourite 'pure' death metal album and Swanö's songwriting is a big part of it.
3. Diabolical Masquerade - Death's Design (8.9/10) and Nightwork (8.7/10) contain some fantastic, original songwriting. A great mixture of heavy/evil and melodic.
4. Dan Swanö (Moontower) - The first half of this album is a perfect 10/10 in my books. It drops in quality in the second half, but not enough to not make it an outstanding melodic death metal album.
5. Witherscape - Both albums are fantastic, especially the first half of The Northern Sanctuary.
6. Nightingale - A good occasional listen, but lacks the variety and dynamics of his other projects IMO. The Closing Chronicles is the best album I've heard from this project.

I haven't properly listened to Pan.thy.monium, Ribspreader, Godsend or Infestdead.

Many of the projects he's been involved in as a producer are also fantastic (many of them highly rated here on MS), there are too many of those to list though!