Should I merge my SPG & Marriott programs? Which one should I keep?

Following the buyout of SPG by Marriott, I’ve now received an email from them suggesting I merge my two loyalty programs into one.
I have the option to keep one number and program or the other.
Currently I’m Good with SPG thanks to Amex Platinum Charge card benefits. This entitles me to an uplifted status with Marriott, so I took that too.
Are there any benefits to keeping them separate?
Which program is better from the two?
I’ve been an SPG member for some time and love that brand and program, but there has to be a rational element to the decision too!

Good = Gold in the original question above. A typo I overlooked in my review before posting, my apologies.

Unless you are interested in earning stays or nights for multiple rooms/nights - possible with more than one account, I personally don’t see much reason to not merge the accounts. They are one and the same now (or by next year). Just a matter of which acct number your prefer.