In terms of map data, as far as I know there's pretty much only OSM, Google Maps and Apple Maps (which is getting a beta browser version)*.
OSM map data is usually excellent, search can be very hit or miss though. You might want to try some of the apps that use OSM data like Organic Maps to see if you get better search results using that. Personally I use both Apple Maps and Organic Maps.
* I also know of Mapquest but it's lacking a lot of POIs and even ways from what I can see, at least in the two cities I've checked.
RCS is a carrier protocol, like SMS