So --- just my $0.02 ---
During my FM residency, had an opportunity to rotate in an SM clinic during my ortho rotation -- this one had a "name" FM doc that had about 90% (if not 100%) of his practice as SM -- was the team doc to a pro sports team prior to taking a faculty position. In my experience, he did a lot of MSK exams, injections, and would order PT but that was the extent of it --- however, in the clinic there was an orthopod who also did SM and did everything the FM doc did but could also do surgical repairs when indicated...and was also doing some interesting concussion research ---
So this depends on what you want to do --- if you like being able to see patients, diagnose, inject joints, order PT and then if they need it, off to ortho -- go FM/SM
If you want to be able to do what FM does but also be able to get in and surgically repair when indicated, go Ortho
Since you mentioned "prestige" as an important factor to you --- I would lean towards ortho --- FM is not known for it's "prestige" -- about 75% of the other residents I ran into from other specialties considered us dolts and about 25% admitted that they couldn't handle having to know everything we knew to the level we knew it.....
But, a word of advice, --- in the end, prestige doesn't matter, neither does $$$ --- I know of more than one surgeon who has mucho dinero yet doesn't know their own kiddos and the wife is more of a trophy --- in the end, my choice of FM was not about prestige or $$$, it was about how my time was spent --- most, if not all, of the people I love and care about work or are in school from 8-5 M-F, so for me, that meant not having to move them for residency (I suffered in a real hellhole of a program) and being able to enjoy the weekends/holidays/evenings with them -- my family will be here long after I've hung up the stethoscope and with good financial management, we live comfortably ---
Yeah, you've worked your butt off to get where you are --- but ask yourself why? If it's only for you, ok; if it's to provide better for your family, find out what they'd be happy with? You kids will likely want time with you as will your wife -- and if they love you, does it really matter what other people think? i.e. "prestige"......
These are questions only you can answer ----