Perk's the better defensive player now, but Shaq's still good (just more limited because he's slower than Perk, not an easy thing to do).
Shaq's still a much better offensive player. Perk's improved tremendously on this front, but he'll never be a guy you can just toss the ball into and know it's either two points or two foul shots.
Perk can play 30-35 MPG; Shaq can't.
Perk's the better player, but there's no reason whatsoever to not have both. Even with all of their limitations, you don't get much more intimidating that KG / Perk / Shaq / Jermaine, plus Davis.
Question, though; if Shaq DOES sign for the vet min, why here instead of Miami? Miami has no real way to structure a S&T with Cleveland to give Shaq more $$. Love to sign Shaq at the min, but not sure we're in the lead if the dollars are the same everywhere.