Depends where you want to
work.
If you are American and you want to find work in America an American Territory or internationally on an American Vessel you will need an American certificate.
American certificates are well recognised. For an American a YM is mostly just not valid. So kind of pointless.
A YM is a lot easier to get. So if you want to work in or on vessels flagged in a Tin Pot Little Ex European country. Its overseas territory or associated
flags of convenience you may find the YM is more widely accepted.
You can get a YM with minimal actual experience on average
boats of 30 to 40 ft
boat. You don’t need to write any exams. You will only have to take a practical exam on a
sailing school boat.
So if you are an American who doesn’t have the required documented seatime for an American STCW 200T certificate.
The YM appears to make a lot of sense. Just be aware the YM is not valid on a US vessel.
If you happen to be from a Tin Pot Little ex European Country.
Obviously getting some form of YM makes much more sense.