I'd take Abreu. Better 5-tool player. He's a lock for 300-100-100-25-30 with considerable upside potential to post much better numbers, like he did last year. I keep hearing how he had a "career year" in 2004, but he's hit 25 or more HRs for 3 of the last five seasons and stole 25 or more bases for 5 of the last six. Yes, he had his best year last year, but it wasn't too far off his career numbers.
Manny will likely post better hitting numbers, but he doesn't steal. He's also two years older, with a terrible work ethic. If I had to choose who would decline first, I'd say Manny no question.
I am the Master. Don't question the Master. Just do what he says and be proud.