Right now, transferring Chase Ultimate Rewards to Marriott points comes with a 50% bonus. In other words, the usual 1:1 transfer ratio becomes 1:1.5. Although Marriott points are still worth a decent amount, around 0.7-0.8c/p, Chase points at 1.5c/p are still more valuable. Even with this bonus, the deal is not especially compelling. Unless you have an immediate need or are just short on points for a hotel booking, we do not recommend transferring. This promotion ends on August 31.
That said, it is still nice to see Chase offering these transfer bonuses from time to time. Hopefully one day we will see one for UA or Hyatt.
The usual 1:1 ratio really is underwhelming. It would be great if a permanent 1:2 ratio ever became available.