It is just a Beta version. You say it is slow, what do you mean by that? Meters later slow? Slow to turn? Mine has gone through the skyscrapers jungle in London without a hitch but i remember issues with phones and antennas before the Nokia N8. If the problem still persists, there is so much a GPS antenna can do, nothing better on iPhone or Android, considering they don't even have a comparable free app at all and that their GPS antennas are nothing better.
Consider I know perfectly the version on Symbian Belle phones, it has all the features you could possibly imagine and stable. Also worth mentioning Nokia Drive Beta on the 920 never crashed. Nokia and Windows Phone will eventually improve it as this is only a Beta version,meaning you are testing it and the app is not complete. My suprise was to find less features compared to the Symbian version, surprise because I didn't research, that's all. It still serves me well.. and it is free! I can't imagine buying world detailed navigation maps with Navigon or Tomtom anymore. They would cost me a fortune as I',m from time to time between several continents.
I don't have any battery issues. Only the first couple of days as the software wasn't completely updated. Now my battery lasts much longer without charge and with intensive use. batteries are batteries..
I also had to notice, I compare my Lumia 920 to a computer, not to other phones anymore. If I do I'm a bit disappointed but I have to remember this is a smartphone, not a computer. Leaving everything: wi-fi, bluetooth, nfc, live tiles, etc, etc.. I mean, not even my Nokia N8 would last that long and Android and iPhone don't do any better while delivering the same computer processing. So I had to reconsider, what I do with the battery and how long it lasts. Sometimes change settings depending on how I plan to use the phone over the day. There is a way to include live tiles to directly click and change the settings rather than having to go through the different levels of the settings menu.
Conclusions? This phone does more with the same power than any other phones I've ever tested or owned.
And when it is the case, I advise anyone to get a battery charger for the office or home and a car charger cable. Wireless charging brings the phone battery use to a different level!