I've been using OnShape a bit more lately. I only just got the iPad Pro. It took a little while to get used to it's idiosyncrasies but getting used to it, it´s ok for small projects, or small edits, but not something you want to use for a full fledged project.
The real issue isn't so much lack of features, though it is missing a few compared to the desktop, including the ability to make drawings. The issue is difficulty in control. They just haven't workout the UI to make it fluid. Feels like selecting etc is a hit or miss affair.
I hope they can make some improvements as I like to be able to work with the pencil from time to time, and find using the iPad will sometimes give a little different perspective on a project that can be good to have from time to time.