All of the Marriott offers are back down to their regular bonus offers.
Here are the best current offers on Marriott credit cards.
Marriott Bonvoy Bold® credit card
Earn 30,000 Bonus Points after spending $1,000 on eligible purchases within the first 3 months from account opening.
This bonus sometimes offers points, free night certificates, or a combination of both. Any points are Marriott Bonvoy bonus points. Free night certificates expire one year after issued.
Annual fee: $0

Marriott Bonvoy Boundless® credit card
Earn 3 Free Night Awards after spending $3,000 on eligible purchases within 3 months of account opening with the Marriott Bonvoy Boundless® Credit Card. Each Free Night Award valued up to 50,000 points - that's a total value of up to 150,000 points! Certain hotels have resort fees.
This bonus sometimes offers points, free night certificates, or a combination of both. Any points are Marriott Bonvoy bonus points. Free night certificates expire one year after issued.
Annual fee: $95

Marriott Bonvoy Bountiful® credit card
Earn 85,000 Bonus Points after you spend $4,000 on purchases in your first 3 months from account opening with the Marriott Bonvoy Bountiful® Card.
The points awarded with the bonus are Marriott Bonvoy bonus points.
Annual fee: $250

Marriott Bonvoy Bevy® American Express® Card
Earn 85,000 Marriott Bonvoy® bonus points after you use your new Card to make $5,000 in purchases within the first 6 months of Card Membership.
The points awarded with the bonus are Marriott Bonvoy bonus points.
Annual fee: $250

Marriott Bonvoy Brilliant® American Express® Card
Earn 100,000 Marriott Bonvoy® bonus points After you use your new Card to make $6,000 in purchases within the first 6 months of Card Membership.
The points awarded with the bonus are Marriott Bonvoy bonus points.
Annual fee: $650

Marriott Bonvoy Business® American Express® Card
Earn 75,000 Marriott Bonvoy Points after you spend $6,000 in purchases on the Marriott Bonvoy American Express Card in the first 6 months of Card Membership. Plus earn an Extra 50,000 Marriott Bonvoy Points after you spend an additional $3,000 on the Card in the first 6 months of Card Membership.
This bonus sometimes offers points, free night certificates, or a combination of both. Any points are Marriott Bonvoy bonus points. Free night certificates expire one year after issued.
Annual fee: $125

My take: Which bonus is best

All of the Marriott cards are currently sitting at their regular offers, making them fairly unexciting.
Of the current offers, I’d say that the Marriott Bonvoy Business® American Express® Card is the most compelling, but it does require a lot of spending to get the full offer.
The free night offer on the Boundless card is interesting, but remember that, while Marriott points don’t expire, but free night certificates do. Unless you use the free night certificates within one year after issue, they’re gone and you’re not likely to get them back. So, obviously, you should have a use for the free night certificates in mind before applying for any offer featuring free night certificates.
Marriott periodically releases increased bonus offers on both the Chase- and Amex-issued Marriott credit cards, so unless you have a compelling reason why you need a Marriott credit card now, I’d wait until new bonus offers get released.