Map questions

I'm trying to decide between the 8x and 920 and am coming across conflicting map info. I realize Nokia Drive is the turn by turn part, and is not currently available on the 8x, but may be a purchase later. Here is where I get confused. When reading about the original WP8 announcement there was a lot of talk about them ditching Bing Maps for Nokia maps. When reading recent review there is talk about the Nokia phone getting better map results then the 8x because the 920 uses Nokia Maps and the 8x uses Bing maps. Do these phones each use a different map app? Are both apps on the Lumia? What happened to Microsoft ditching bing maps in WP8? Won't this delay the WP8 updates to the Lumia line due to it needing custom firmware?