I ran small blocks for years and loved em. Bigger is better though. Outran a bunch of supposedly "900 hp" bigblocks with my 550hp 406.........anyway, IMO, up to 550-600hp, a sbc is the way to go and expense is about the same. Beyond that, I'd go bigblock. Way easier to make power and probably cheaper in the long run.
Like I said, I've been a sbc fan forever but got the chance to buy a low run RM522 from a buddy of mine a couple of years ago. Wow! Compared to a small block, it just pulls and pulls and pulls........all the way to the stripe and beyond! I won't go back to a sbc unless I build another FED. Then maybe.......
Johnny