Why must it be one or the other out of those two?! There's just too much of a drastic color and size difference for me to be able to make a decision...why no middle ground? 2ct H/I VS2 perhaps!? I think I'm too color sensitive to handle a MRB J (I also feel AGS is a bit softer on color so to me it would probably be more like an GIA K). But 1.65 is small for my size 7 finger! Ultimately, I wouldn't be happy with either.
I am not seeing a 2.5 J SI1 ACA, so is the stone on hold? What is your budget? Because I agree with others who said they'd choose an H or I color stone between those two sizes. I don't think the cost is the same for stones with those two specs. Did you maybe mean 2.05 cts for the J stone?