Hey, first of all, for our field, honestly ios is truly lacking. When I had my ipad pro i really tried to make it work but it is just way too inefficient for a fully integrated workflow.
The ipad is only good for the preliminary design process, ill list the apps I used.
- Morpholio trace is the best app for designing as it replicates tracing paper quite good.
- Graphic by indeo works for vectoring drawings, it however sucks when trying to make it work with illustrator, the exporting as svg or pdf sucks.
- Autocad 360, good concept but honestly it WILL make you waste time rather than using the proper client for cad work.
- Shap3d and umake, never really got into it, im just too efficient with sketchup to even want to try/use them more. Learn formit by autodesk as eventually it will integrate with revit (HUGE PLUS.)
All in all, if OSX sucks for the lack of architecture programs; ios is exponentially worse. Preliminary design does work with it but you will be using your laptop for production quality work nevertheless (construction documentation, design panels, renders, modelling etc etc.). It will be hassle for you to integrate the ipad with laptop/desktop.
Ps.If I were a senior architect/boss and had hired interns/architects working for me then it should work quite good since you will literally be designing the concept by sketching, and ur employees would make the production documents. That I believe is a realistic scenario were the ipad would certainly shine. (Still believe a surface pro is the better purchase but that is another topic.)
Sorry for errors, Peruvian here!