Telenav is pretty decent. I went from a TOM TOM 910 to Telenav on my BB 8800. Its nice, though the traffic, at least in the DFW (Texas) area, is lacking. I disregard it most often, and turn off on frontage roads and let Telenav figure it out and reroute me. Lately though even Telenav has been slow or non responsive. The maps work fine, but the data it pulls will lag, or tell me it needs to retry. Its frustrating when your .2 miles from a series of quick turns, and it does this. This could be the internet access to the BB (Sprint), though while this is happening, I have gotten emails to the phone.
I use it every where I go, not because I lack a sense of direction, but because I am a road IT admin. I drive from clinic to clinic some I have never been before, others I goto weekly. But since I do not go back to "base" every trip, and some of the clinics are 30 miles apart from each other in random directions, Telenav is helpful.
Honestly, if the iPhone were to get Telenav, or something similar, I would look at it, but probably not buy it. Since I already have Telenav on my BB.