Hey AllisonSanders . The only thing I would say is more "complex" about canvas is that there is more data to update and write to tables in Currents vs a Campaign. For example, Canvas Entry table is not needed for Campaigns.
Other than that, I have run some extremely complex liquid with catalogs, connected content and conditonal logic. The only thing I can say on that is use case vs if is a little better. The other thing I ran into was when you have extremely high volume (1B+/dayy) and a lot of conditional logic, it could take more than a day to process (because of connected content rate limits) and that could cause some issues with frequency capping. This is not a canvas vs campaign problem per se but you wouldn't run into this problem because you'd need many campaigns to run at the same time vs 1 canvas, so it's easier to get there with a canvas.
Hope this helps!