I had one... I put JJ ecc83's in all the preamp spots and it darkened it up a bit (stock it was just real bright). this tamed the highs and gave it a bit more edge on the gain. I used the fluid drive and after a bit of eq'ing it was a good amp. Its more of a Marshall British sounding amp.
The clean channel was real nice and full... so far it is still my favorite Mesa clean.
I wound up going with a Dual Rec triple channel just because I liked the amount of gain it had over the Trident plus the option to go with 6L6 or EL34's..
But the Trident series 1 is still a good amp... just have to "tweak" it to your liking.