Ive played both classes for some good time.
I only say this
Engineer = now a support class with fervor/seal/aop and has some a0e heal and stuff
Scout = Pure dps class with variety to choose from melee or ranged spec, also nowdays they have sum fun tanking abilities

(actually did a maze gold run with scout tank, that dude was also top dps
pvp survivability = defo scout wins!
pve dmg = scut wins
Getting parties to astral, well engi wins just a little, only seal to offer apart from scouts buffs
Sorry i could give alot more info, but i let others give their feedback too xP
So here's my 2 cents or how u say