Here are my thoughts on comparing the two horses, for what they are worth, probably nothing
First, I throw the earnings out the window. Of course you're going to earn over $7,000,000 when you win a race with a purse of $6,000,000. Hell, Giacomo's a millionaire, so is Lawyer Ron, so is Cherokee's Boy for that matter. Does that make them "good" horses, better than non-millionaires - no. It means they were well placed. Comparing times would indicate that many Japanese based horses were better than what is running in America and Europe because the purses in the far east are HUGE.
First, Ghostzapper won 4 Grade 1 races in five tries and was never off the board in either. Pleasantly Perfect took 3 Grade 1 races in 6 tries, and was off the board twice.
Biggest difference for me though is the fact that Pleasantly Perfect needed a race to set up for him, while Ghostzapper made his own breaks. Pleasantly Perfect NEEDED a strong pace, or he was going to be hard pressed to win. Ghostzapper set his own pace or closed from last...didnt matter to him.
Not going to compare final times, because they vary from track to track, day to day (i.e. what is good - what is bad - what is average). We'd have to go back and view a ton of charts, stats, etc. to see what was quicker. I'm personally blown away by the 1:46 1/5 that Ghostzapper ran in the Woodward for 9f, but the track could have been playing ultra quick that day. I dunno if it was or not.
I'm basing my opinion purely on the visual aspect of the game. I watched Castellano sit like a statue on Ghostzapper's back and his cruising speed alone was quicker than any other horse could offer. Castellano never asked him in the Met Mile and he still went the three quarter in 1:08 2/5 and the mile in 1:33 1/5...thats damn impressive. Plus, I cannot overlook the fact that he won the 6.5f Vosburgh, the 7f Tom Fool, the 8f Met Mile, the 9f Woodward, and the 10f BC Classic. How many horses are as good around one turn as two? Obviously not Pleasantly Perfect, who never won a race under 8f and never won a Grade 1 less than 9f.
Just my thougths...