What's the difference between

• WAVE
• Broadcast Wave
• W64 (SoundFoundry WAVE64)
• WAV (Microsoft)
• WAVEX (Microsoft)
• Soundcloud - WAV

and which one is best to use?
 
Plus there are bunch of other audio export options that I can't find in the help docs.  Not sure how to proceed.
 
What I'm doing is converting my MIDI music to another format so I can use them as backup for live performances.
 

Wave (the default) should be fine. If the file exceeds the size limit, SONAR will automatically use W64.

Broadcast wav includes a time stamp of where the wav begins on a timeline. Useful for collaborations with others who use a different DAW.

• WAVE - default wave format - uses Cakewalk encoder (will auto write wave 64 if file size exceeds 2 gb)
• Broadcast Wave  same as wave but with special header to specify time stamps and other metadata
• W64 (SoundFoundry WAVE64)  extended format for wave files that exceed 2GB
• WAV (Microsoft)  - similar to default wave but written by libsnd encoder
• WAVEX (Microsoft) - Wave format extensible format, has different file header used for multichannel wave files typically, and also for 24 bit wave files 
• Soundcloud - WAV   - this exports a wave file for upload to soundcloud

 
The other export choices are all various audio file formats. Google them and you will find more info about them.