I have onx (hunt and offroad) and no experience with Gia. I would do a trial of offroad before purchasing it. I have had offroad for a year here in Colorado and it has gotten significantly better in that time. When I first got it, most trails around me and our cabin were unmarked. As the year went on, more and more trails were added which is why I recommend trying it to see if your area is covered.
Unfortunately for finding private, public, etc land, I find myself hopping between offroad and hunt. They do not talk to each other and each have their strengths (hunt = land, offroad = trails). I just got back from a 3rd season rifle hunt and the trail system in onx hunt was atrocious in our unit.
All of the above is through navigating through the app on my phone. I have played with hunt on the computer to mark waypoints but I have not with offroad. I do like that in the offroad app on a phone, if you click on a marked trail you want, ie Holy Cross trail, I can then click the trailhead and navigate to it through Google maps.