Interesting review but last summer I tried (
and reviewed) 3 of those free offline navigation apps, NavFree (USA), OsmAnd, & Mapfactor:Navigator (all based on the Open Street Maps database) and
I found Navfree to be the best because I valued some things not covered in the OP's post.
1) Only NavFree allows you to navigate to a contact in your address book!!! That's critical for me. The OP complains about creating "Favorites" in NavFree. For me, my address book contains my favorites. I don't want to type in addresses on my phone every time I go somewhere. That's torture. (And I found it easiest to add "Favorites" anyway.)
2) Only Navfree consistently let me enter a house number for a destination, like "123 Main Street". The others made you rough-out blocks or pick cross-streets. C'mon. That ain't door-to-door navigation. So lame.
3) Only NavFree had an intuitive user-interface. No instructions needed. Very simple. With the others, I struggled to figure out how to set destinations, & favorites, or find points of interest, get a direction list, etc.
4) NavFree had the easiest map downloading. You just hit the "Upgrade" button and then select which state you want to download. If the download gets interrupted or if you pause it, then you can resume from where you left off (unlike the others). It's 2.6GB for the entire US (or about 50MB/state on average). A big state like CA is ~200MB. A small state like RI is ~5GB.
It was like torture downloading MapFactor:Navigator maps. The user interface was not intuitive, the downloads would fail several times, and then not resume from where they left off so I'd have to start all over. OsmAnd was OK in this regard but was limited to 8 maps in the free version.
5) Navfree and OsmAnd both had nice, clear, bright, attractive maps and interfaces. Navigator did not.
NavFree can be kinda laggy and it doesn't have anywhere near the polish of Google Navigation, but for a free backup navigation app, it's pretty darned good, and IMHO, way better than the other two, which I found frustratingly difficult to use.