HH diamond and Bonvoy Plat here. As usual, it depends on your travel patterns and cities visited. Some places outside major cities just don't have many Marriott hotels, some places have both HGIs and Courtyards (I prefer HGI) and Ritzes and WAs. I will say my upgrade success has been better at Bonvoy hotels the last year or two, which is nice, but if you are traveling for work, it often doesn't matter. I know you said your company pays for breakfast, but when you travel for leisure, that could make a difference -- but breakfast depends on which properties you frequent for personal travel. One definite benefit I enjoy and use often is the 4pm checkout with Marriott hotels, it seems much harder to get past 1pm with HH properties.

Like Dublin_rfk said, why change without standout reasons?