Since I like equally the look of either blue trim or ivory trim, I made a decision based on practicality of installation, instead of appearance. I'm going to paint the trim blue so that I can adhere it to the house before I paint it.
I can take a piece off, glue it on, tape it in place while it dries, then take the next piece off, glue it, etc... If I were to paint it ivory I'd have to take all the pieces off and label them, so I know where they belong, before I could paint them. Then once they were dry I'd have to figure out where they go....then, after they were on the house, I'd have to do some careful touch-up sanding and painting.
If I don't get a trim piece glued on exactly right I can hide the mistake with blue paint. I can't do that if I have to maintain a crisp line between the ivory trim and the blue siding. Also, any of the white adhesive that oozes out from under the trim can be painted blue so it will blend away.
The corners are bound to be the part of the house that is going to get dinged. Touch ups will be much easier if the trim is the same color as the house.
Blue will be easier.