If Celtic can continually qualify for the group stage of the Champion's League, it would be a decent move for Agudelo. That's a huge if, considering the recent performance of Scottish teams in the qualifying round of the Champions League.
Other than that, it's pretty much a lateral move from an upper tier MLS team (NYRB, not his recent Chivas foray) to Celtic in terms of league play. Celtic is certainly a better football culture for a player to develop than any MLS club. Sacha Kljestan moving to Anderlecht in Belgium is a better move, considering the recent upward trend of players coming out of that league. I think Agudelo would be an excellent fit at a competitive Eredivisie side, like a PSV, AZ, or Feyenoord. It would help him to be in a less physical league than the SPL, considering his recent rash of injuries.
I may know nothing about Scottish football, but the UEFA coefficient has the Scottish league ranked below such stalwart leagues as the Swedish Allsvenskan, the Romanian Liga 1 and the Belarusian Premier League. LINK
This post was edited on 11/23 at 3:08 pm