First instinct, are there any family politics around the diamonds? Will one grandparent be disappointed if it's not chosen? These kinds of issues are often a MINEFIELD.
Here's my take on the two stones.
Cushion or round cuts with halo settings are more "on trend", emphasis on trend. They are ubiquitous. Almost every recently engaged or married woman in my office has one. There's a reason why this style is popular. It's a beautiful way to set diamonds, and it gives more finger coverage for smaller diamonds. But I think that the style will be dated.
A classic, well cut pear is a gorgeous stone, and a little different.
I love the idea of the pear in a simple platinum bezel setting. Or you can go for having tapered baguettes on either side too. A colleague of mine has a 3-carat pear that has a spectacular cut. It's quite beautiful.