Ambivalence

The Mets have signed Yoenis Cespedes for 3 years, $75 million, with $27.5 million in the first year and an opt-out for Cespedes after year 1.
I like the deal. I think the Mets got a good player for a short contract. It's a lot of money, but in baseball nowadays it's better to pay more money for fewer years, than to get a long-term discount.
The Mets get an excellent hitter, a right-handed power bat, something they didn't have.
If he hits the way he did last year for the Mets, at an MVP level, he will make the entire lineup better and be well worth the money.
And he will do it all while giving the Mets another year to evaluate Lagares and Conforto while not totally relying on them to perform.

BUT... This move really hurts the Mets defense. Lagares is a great centerfielder and Yoenis is a very good leftfielder. Cespedes is an average centerfielder and Conforto was good last year, but there's reason to believe he benefited from a small sample size.
The Mets are spending a lot of money on two bad defensive middle infielders (Cabrera & Walker) and weakening the outfield too might be a bad idea, especially in a big park.

Also, Cespedes is not as good as he was last year. His OPS in 2013 and 2014 were 736 and 751. Last year he improved to 870. If he reverts to sub-800, he would not have the positive impact we hope for. Also, he would not have the suitors next year and would like opt in for two more years with the Mets.

Lastly, I don't like his attitude. He's made some bone-headed plays and he doesn't always try hard.

In summary, if we get the Cespedes of late 2015, the Mets made a great move.
If we get the Cespedes of 2013 & 2014, we're stuck with a basically average outfielder at an exorbitant cost for 3 years.

Only time, and Cespedes will tell.