Limited by only 4 characters... My last choice?

I have to decide what my last character slot will be :

Mo/Me

or

Me/N

Currently, it is a level 10 Me/N and is in Yak's bend. Although, I like the idea of a Mo/Me. The combination of "Channeling" with healing skills reduced in cost sounds very, very tempting... while the power to steal life and mana in any way, shape, or form has already become one of my favourite things to do. I wish the Guildwars creators would come out with a patch for more character slots, or an expantion pack real soon with more character slots... lol.

My other three characters are a level 20 E/Mo, a level 20 W/N, and a level 20 W/Mo. All are very unique and different from the other.

With two more character slots, I'd probably go and make my Mo/Me, and a R/?.

Anyways, could someone tell me which is more fun/better for dueling? I know Mo/Me are desired as team-mates in duels.