I use both... the scuba tank is first... which gives me 3000 psi when full... but now.. after 47 fills into my gun... it's down to 1600... so... i use a hand pump to bring it up to 3000.. which is easier than most people make out...
the tank is quick... gotta get her filled up again... and i have 4000 psi tank on the way... which will last me along time...