Hi Adam,
There's no right or wrong here
but TWO EXTRA INCHES of aperture is TWO EXTRA INCHES OF APERTURE!!!!!
It equals to 44% more light. The one drawback is physical size.
One way around this is the Meade Lightbridge, a 12" Truss.
I have one and it fits into my Ford Laser, with plenty of space to spare.
If you're after a EQ mounted scope, then it's a different story a 12" on a EQ6 is a hefty size and weight and so a 10" on a HEQ5 would be better.
