I just took a holiday trip from TX to MS, using Waze as my navigator for the first time. I was mostly impressed with it, but encountered several oddities that I think could be addressed. I definitely like it better than my Garmin unit, but I don't know if I'd rely entirely on Waze yet. I'm using paragraph form instead of bullet form because some of the problems are interrelated. I'm using Waze on an iPhone 4.
Waze initially suggested a route involving I-20 that I know from experience is 70 miles longer and involves lower speed limits. I instead opted for the I-10/I-12/I-59 route that I know is fastest. Waze knew this route was faster and even had a ~50m sooner ETA for it, so why was a longer and slower route chosen by default? I've had this happen with shorter routes too. Just the other day my ETA of 1 hour 10 minutes dropped to 45 minutes and all I did was ignore Waze's attempt to route me off of a clear highway through a series of subdivisions and traffic lights.
Loss of 3G connection causes some really dumb things to happen in the client. As I traveled across dead zones in LA and MS, I experienced failure to load map tiles (which is understandable, but never happens with the pre-loaded maps on the Garmin unit and would make a nice Waze feature.) More concerning was occasionally the highlighted route would just disappear. In these areas, I would literally see a 10-mile gap appear in the route that Waze was happily displaying moments before. When I hit the gap, Waze flipped out, zoomed in as close to my car as possible, and continuously displayed the "talking to the servers" indicator while urging me to "proceed to highlighted route". After a few miles, it'd pick up the trail again and all would be normal for about another 10 miles, when it would repeat. This constant change in zoom and animation of icons was very distracting while I was driving. I think Waze should stick with the route it already has if it loses its connection, and display a much more passive indication that it's not communicating well. The second attached screenshot shows me driving along I-59 on the clearly highlighted route while being told "Proceed to highlighted route" and forced to watch the car-hamsters spin.
This happened at one point where it clearly had a decent connection, because it was super-concerned about me deciding whether a reported police sighting was still there. Between the alert, hyper-zoom, and "I can't see the server" indicator, I couldn't see anything about my suggested route, which is the most important thing on the screen! The first attached image is a screenshot I took of this phenomenon.
At one point in the trip I completely lost signal. I don't know how long it took, but Waze basically gave up on even trying to connect. I noticed I'd had "Searching for network..." indicated on the screen for 30 minutes and figured something was up. I closed Waze via the multitasking tray "force quit" method, then when it restarted it found the network just fine.
Another problem I've noticed involves defying my preferences when communication with the routing server is lost. For example, when leaving my office I usually don't want to take the toll road unless traffic looks /really/ bad. It saves me a couple of bucks and I actually use more gas on the toll road. So I tell Waze, "No way, use this other route." Usually my signal drops at some point while I'm getting out of the parking garage. When this happens, Waze silently changes the route back to using the toll road. This is minor, but would be very aggravating if I were using the app to actually navigate somewhere unfamiliar. I had it happen in a couple of spots along the TX -> MS route where Waze thought it could talk me into hitting I-20 again.
I think Waze should remember if I've chosen a non-optimal route for some reason. I think if Waze knows that route, it ought to not pretend it doesn't if it can't communicate with the Waze servers. I understand that the app's primary value is its ability to route you around traffic, but I think it should respect my choices if I think I know better.
I'm not griping and whining that Waze is terrible; I very much prefer it to my Garmin unit. However, these improvements would make it much more convenient for use in areas like Mississippi with inconsistent data coverage. Those areas happen to be the places where I want to use an app like Waze the most.