Q: How much free disc space should be on a new MBP?

On my brand new MBP, my first mistake was I did not immediately time machine the new mac or record the "available" disc size in it when it first came out of the box.

My next mistake was I ran migration assistant twice, and it failed with unspecified errors both times.

Now when I go to Apple->AboutThisMac->Storage, it reports OTHER as 121.48 GB, and Audio/Apps/Movies/Photos/Backups together are several dozen GB in total. So OTHER is taking up most of the used disc space right now.

Disc utility says the HD has used 151GB total, with 348.1 GB available.

Capacity of the disc size is 499.1GB

I have not yet put any data on this MBP, unless the migration utility did it without me knowing it and didn't delete it when it failed.

What exactly is OTHER data?

How can I find out if my failed migration attempts has put 100GB or thereabouts on this machine that I can safely delete?

How much disc space is USED right out of the box on this MBP (2014 13" retina, 500gig drive)?

Thanks!!!!