What is your reason for selling it? I use onxmaps on my phone and this past year my phone was giving me issues with my saved maps. My plan was to get a Garmin. But I haven't started investigating them yet. Your post caught my eye. I am assuming since it's wifi capable I could get onxmaps through Google play?
Had 2 buddies back out after 5 of us agreed to get them. Yep, it's an android based operating system. I use my onx chips with no problem. If you're used to using your phone the format on the monterra will be very familiar.