I shoot mostly LF, and use MF (6x6) sometimes. I use the MF with both WLF and a prism - and for me, I tend to use the prism more when I am hand-holding the camera, and I appreciate the convenience of having the meter built in to the camera. Most of my shots though are on a tripod, where I don't use the built in meter, and am more likely to use the WLF.
All a matter of preference - and to your question of how do you get used to images being reversed - the answer is 'with time'. I actually find it to be an advantage to have the image reversed, as it allows me to think about composition more closely.