I've had a ported set of 906 heads, and a ported set of 915 heads. Lost both after 5 or 6 years of bracket racing and occasional nitrous use. While I believe it's possible to get good numbers out of them...it just doesn't make sense to me to spend all that time or money on 40 year old castings that are prone to crack.
Bought a set of Edelbrock RPM's, broke two engines under them in 8 years of hard running, then cleaned them up and sold them to my brother for 75% of new price, and he's got three years on them.

Bought a set of Stealth CNC heads, and bolted them straight on my street 440, love them so far, and like the Eddies, I bet I can recoup 60 to 75% of my investment if I decide to re-sell at some point.

Bottom line, if I'm going to spend 1000-1500 on CNC or hand porting, it only make sense to spend that on a solid, reputable, and repairable casting.