I've used the iPad since the first one and now have the 9.7 pro (third iPad).
There are a lot of things I like about the iPad, including using iSailor for NAV. We only charter
because we can only get out a few times a year. Sometimes the iPro is the only NAV I have and sometimes it's used as a secondary to the plotter if the boat
we're chartering has one.
For me, it's about 95% of my business Win10 PC. I have written some MSAccess/VBS programs that I need for work which do not work on the iPad. However, I can use the TeamViewer application to connect to my PC and do these specialized applications.
I selected the iPad 9.7 over the 12" because of the portability. However, sometimes I wish I had the larger one. I'm used to my 42" 4K UltraHD TV display at the office and the smaller iPad obviously isn't nearly as large.
To really use the iPad, I use and recommend using a good keyboard. Mine is the Logitech Create. This provides some protection for the iPad and quick connection to a keyboard without charging
the keyboard (power comes from the iPad).
I also have the iPad pencil, which I use for handwriting notes with Notability.
The other main application I have is GoodReader, although I don't use this as much as I used to because Notability does a lot for me.
*All* of my files are on Dropbox, which means I can access any of my files from any where when I have cell coverage or wifi
I'm not an "Apple geek" and think Apple is the only brand to buy. I looked at the Surface Pro, which is really nice. However, it still seems overpriced (IMHO) and probably overpowered for my needs. I have not looked any other tablets or smaller laptops, so I can't comment on them.