In my experience, an 8 gallon kettle is rather limiting. You can't do longer boils for batches, since you won't want to go above 7-7.5 gallons at the start of the boil (even with fermcap). If you factor in your loss to trub and such (in fermenter) and want to get 5.5-6 gallons into primary, your limitations are even greater. Those two extra gallons of headspace is a lot more valuable than you might think.
Personally, I get 6.75-7 gallons into primary. With loss to hardware and such, that means I usually end the boil at about 7-7.5 gallons. Luckily, my keggle can easily handle ~14 gallons at the start of the boil.
I really do like my Blichmann burners...
As unionrdr says, Blichmann gear can be costly. It's well engineered, and great if you don't have any tools, and cannot use a drill to save your life. Otherwise, with some decent thought, you can make a really nice kettle/keggle for less money. Depending on the option you go with, though, the cost difference could be rather small.