I did try the app on my current phone, the Moto G5 and it was OK. I wish there was a strong web based program like Microsoft did with their office suite.I got the free trial of the autoCAD app, and it worked well for opening existing drawings and making small changes. Spent a couple hours one evening trying to create something moderately complex and finally gave up after accomplishing almost nothing. Some of it was lack of familiarity, but it just seemed way too hard and the available tools are limited. The price is certainly reasonable, but I really don't need it.
Tried several other CAD apps that I wasn't impressed with. Shapr3d is the coolest app I've tried, but I really haven't spent mucn time with it. It seems more like a 3d design app instead of a general CAD app for creating technical drawings. Need to spend a little more time with it though.
As I said earlier, I'm gonna learn a lot of stuff in a short time and I need a note taking device with the ability to tag and store information. That's what I'm gonna use my iPad for. Later, if things doesn't improve with iOS apps, I would have to get a surface pro.