Which is better?
or
To me, the Print Module seems easier because I don't have to make temporary virtual copies, however I am wondering if this has any downside.
The goal is to upload the images to an online print service to get prints made.
I think the primary difference here is conceptual. If you view the target aspect ratio as the ideal form of the image, it might make more sense to crop early in the workflow.
If, on the other hand, the ratio you are choosing for printing is just what you're doing this time and the image happens to be a less convenient shape in what you consider to be the "full" form, you might prefer the Print Module approach.
Either way, the result will be the same, but different processes might fit your ideas better.
Since Lightroom is non-destructive until output, there shouldn't be any difference. The only thing I could think of would be that it might be trickier to select the exact size and orientation of how the image is cropped, but otherwise there should be no differences that I can think of.
In one key way, they aren't the same. When you do this through the develop module, you are controlling the crop that changes the aspect ration. When you do this through the print module, you are ultimately allowing the system to make cropping decisions for you.
Depending on the image, those decisions might be fine. But there will be images where it won't be.
I've been doing experimentation on this recently, and my decision is that aspect ratio decisions are something I need to control on an image, which means, as the original poster noted, virtual copies and some time in the develop module. But after trying a few different ways to do this without the manual steps, I've come to the conclusion it's necessary, or I'm going to have images that "break" from unacceptable crops that I need to go in and fix manually anyway. I might as well build ONE workflow where I crop them properly up front than have to override an automated workflow repeatedly with manual "fixes" to get what I want.
