GMs playing Characters

There is a stigma against a GM playing as a Character in their own game. Especially if they want to play -while- GMing.
Common things said are they can't stay objective, that they will use knowledge that no one but the GM knows, that it will slow the GM down having to both GM and play, and the list goes on for nigh forever.

I'm a GM that calls BS. Most of the time.

I am, and know, quite a few GMs that can keep GM and Character two separate things, don't slow down play and do not give themselves the main role in the game.

I also know quite a few GMs that can't stop from doing the above even just being the GM, forget it if they want to play a character.

For about 3 months I GM/played in a World of Warcraft tabletop game (Great game btw, uses DnD 3.5 rules and fits WoW play decent enough) and never had an issue keeping my "team" as normal characters. My players also said I did a great job keeping things separate and the game moving smoothly. I say Team above because I actually was playing as 4 different characters, depending on where my players were in the world would decide who I played as from Troll Warrior/Rogue, Human Wizard/Warlock, Dwarf Tinker or Human Tinker/Warrior.

Flip side. I played in a game where the GM decided to also play as a character while GMing, and took 15 minutes not only to decide when any player did anything, but took the same amount of time when his character did something. Very unorganized. The largest example I have of this is a 7 hour (without breaks) boss fight. At the end of said boss fight not a single person was happy with the game and about half the players left (stating that session 'as the last straw') I really feel for that GM and wish him luck in getting better organized. He had great ideas, just couldn't pull them together.

So what type of GM are ye?
Would ye keep your cool/morals and play fair if GMing and Playing or would ye be better off just sticking to GMing only?

Mission 02 - Distress Beacon

We had our second mission on April 4th and again I am amazed at my players. This time around it was the daytime players (I have three groups in this game it seems. Those that can play during the day, normally around Noon EST, those that can play at night, normally starting around 20-21:00 EST, and those that can swing both) and I was really impressed with their reasoning skills. Between the group I had four enemies planned in total, either as four separate fights or two fights with two enemies depending on how it happened and they were able to completely get around those fights through genius RP.
Using Ifrit (a fire elemental summon) they tracked down some Fire Elementals and instead of fighting them they spoke to them (again, I love groups that aren't Hulk Smash! in each session).
The next part that happened I wasn't even planning until the next mission but the RP and way it felt was just too good to pass up. I had the group of Elementals 'possess' each party member one at a time and go through said party member's memories. The purpose of that was to see if the party member was viewed as clean or tainted in the Elementals 'eyes'. If found clean nothing would happen, the Elementals would float out of the character and state they are clean then wait for the next character to give permission to test them. If found tainted the Elementals would 'purge' them of the taint, taking said character to 1 HP, then state they cleaned the taint and said character is now clean.
Given I made the clean/tainted test as a % roll made in secret, I'm really surprised that only one character was found tainted (and find it interesting that it was the Angel). All the characters taking place in this test gained a specially made Advanced Trait (hard to explain these... think plot-point hooks that a player can activate to get cool benefits, or impose some difficulty in return for points to use toward activating the cool benefits part.)
I'm very eagerly waiting to have Mission 03 - Terraforming. Where it continues "Beta's" issues as seen in Mission 02.


Here is the link to Mission 02.