Wipers are the same on all I think.
Some on here will try to say it's about how clean your windscreen is, but mine are defintely completely random. Have been since brand new. I try to avoid and use single wipe (up push) or constant. Feels like going back into the dark ages, but what can you do!
As for Media Player and B&M. it's pretty flakey at the best of times. I've used 2, 8, 16 and 32 GB pendrives. With each one, some songs play and some don't. As the last poster suggests, think it's all about the tags. I'm experimenting with about 8 GB of music on a 16 GB pen drive at the moment. They have all had their tags updated and file names tidied up. Will take a few days to find out if everything is playing.
Other thing to try is the Ctrl+Alt+Delete option. Disconnect the battery negative lead (clamp type) for 10-15 mins. This forces a reset on B&M and often solves issues.