To GM or not to GM: That is the question?

Whether 'tis nobler in the mind to suffer
The slings and arrows of heavy game criticism,
Or to take arms against a sea of system backlash,
And by opposing end them? To die: to sleep;
No more; and by a sleep to say we end
The heart-ache and the thousand natural shocks
Of a lack of players, 'tis a consummation
Devoutly to be wish'd. To die, to sleep;
To sleep: perchance to dream of a great home group: ay, there's the rub;
For in that sleep of no games to GM what dreams may come
When we have shuffled off to a convention for games?

So I am having a little bit of a crisis at the moment as far as my GMing games goes. I seem to have lost faith with my ability to GM at conventions as I have fallen under some heavy criticism

I am really struggling to keep my home group together. I have had some excellent players join over the last couple of years yet they seem to find excuses when to next session is scheduled not to come.
Now I am a good host – I provide a cooked meal and snacks as well as a full fridge of drinks [beer and soft drinks], I run a reasonable game with a good story, I am well organised with nice maps and handouts. The setting is fairly cool though I do know that many people do have an issue with Glorantha as a setting.

I do also know that many people dislike the HeroQuest system, but I didn’t expect it to the point that several people have condemned my games on the RPG con circuit here in the UK. This is just not an attack on HeroQuest but my games in general. Now it could be just rumours but having heard this from two different sources is troubling. Bad-mouthing my games seems a little bit cruel and vindictive and the rumours are appearing to spread by word-of-mouth.

It is now getting to the point that I may have to give up GMing games at conventions all together.
I plan to run a few HeroQuest games at Tentacles Omega, a RPG convention that takes place in Germany at the end of May this year, and get some detailed feedback from those games.

I may just attend less RPG conventions in future; I’ll just concentrate on help organising some conventions that I am involved with instead.
At Furnace I'll not run any games for instance.

I am just not sure what else to do?