Out of the box, there are three background music settings:
IMHO, the two “Color” music themes sound like some New-Age hypnosis background music, whereas “Legacy” (from FSX, if I remember rightly), seems more fitting.
Which one do you use?
I use Color 2.
Legacy is nice itself, and you’re right it’s the same music from FSX. But that’s just the thing for me, it belongs to FSX. MSFS is a new era of simulator, so it needs to be distinct and different for me. I’m not a sentimental person. I always go with the change.
I’m a Legacy music user! I love the grandiose feel it gives when I open up the sim 
I use the Old FSX legacy music. Kind of sounds like Soaring over California music, at Disney California Adventure.
I use legacy and love hearing it when the sim fires up.
While I do like the legacy music I use the default one instead. It seems to be the only selection that has two different music tracks for the loading screens and the menus. That way I can have the sim load in the background while I do something else and hear immediately when it’s done loading.
No screaming guitars and no double-bass-drum in all of the choices 
Music is disabled on my end, but if I have to choose I would take the Legacy option.
Maybe they should offer a “custom” sound option?
Or, you can do what my eldest granddaughter does when she plays on her computer - she disables game music and brings up something from the web/Spotify/Etc. and lets it play in the background.
I turned music off a long time ago. Is it possible to have music in the menus but not during flight now?
Good idea
I use the stock color as it goes hand in hand with the loading screen however I’d love to see more styles down the road - one which always comes to my mind is the “Crimson Skies” menu theme when flying the Beech Model 18, the Staggerwing or the Hughes H4 
Personally, as a head-banger, I don’t much like any of it. I keep the newer music playing during load-up just so that I can hear the change when the home screen hits. Back in the FS9 days, the music was an mp3 file that you could change out. I’d pull one out of my collection, rename it, and drop it into the sim folder - then jam during loading and plane selection. I used things like “Learning to Fly” by Tom Petty, “Learning to Fly” by Pink Floyd, “Learn to Fly” by the Foo Fighters…
Oh man… I loved Crimson Skies. I wish they would make a remake with modern graphics. That would be incredible.
Yes, it was totally arcade but the storytelling, music and style was just perfect!
Actually, even when Legacy is selected, there seems to be three different music phases:
All three themes are different and distinguishable.
Hm, that wasn’t the case the last time I tried it (perhaps a couple of months ago). It simply played the FSX theme all the way through.
Legacy. Nothing beats the sound that got me though childhood and my teens
I turned it off day 1 and haven’t turned it back on since
It’s as annoying as the ATC.
