Who is a better fit for the Suns Shaq or Sheed?

If you remember when the Pistons imploded in their series against the Cavaliers and after that the Pistons were inquiring about possible trades for Rasheed Wallace. There was an interesting rumor posted on yahoo in which Joe Dumars inquired about Shawn Marion. The trade talks weren’t serious but however which players would be better for the Suns now not in their prime but in their present condition. Since the Suns could've had Rasheed if their demand last summer wasn't so high for Marion