As I said in another post TM, Miasma is pretty whimpy depending on your skill set.
I am running a whammy, I only use EoO, Concecrate, and lighthing strike. Like Cerveza says, some are 4 hitters some take 12. As long as you get honor up the drop pretty easy either way. I carry G Cure pots with me because his poison is pretty nasty. I run with a Faction + suit so have all 70's resist.
I go in where he spawns, honor and run out between the two buildings outside. Miasma respawns almost as soon as you kill him, so I like a little time to loot. He CAN have GREAT loot. Here is a example of a bracelet I pulled off one this morning.
Int +5
HCI 12%
DCI 11%
DI 11%
Energy Res 12
Plus like is stated, you have the chance to get some martys, para chests and set pcs. He always carries between 2100-2600gp, so bring a bag of sending.. I go outside and recall home when I am loaded up with chests LOL.
You play my shard, so if you want to give him a try, let me know, I can bring a mage up to heal you a few times til you get the hang of him.
Toptwo