Sorry I seem to argue this every year, but after a couple years in search and rescue and dealing with marine clients I feel it is an informed opinion.
I agree with a few others that an iPad should only be used as a backup and with an external gps. Yes, some people have success but also a lot of boats run aground when being piloted with phones and tablets. A mdf is hard wired to your battery and depth sounder sonar and works 99% of the time, my Bluetooth headsets after a year or two 70-80% of the time they connect. My iPad crashes and has distracting apps.
An affordable mdf on sale is irreplaceable in my opinion and likely that of anyone in coast guard, boat repair, etc. C-dory Owner’s have 10-100k boats buy a $500 mdf.