Sailed in Aqua Class twice this year (Solstice and Reflection). Loved Blu! Service wasn’t great on Solstice (suspect there was a lot of new staff) but great on Reflection last month.
We like the smaller dining room and find the menu options nicer. I’m vegetarian and there were always options on the Blu menu for me, but was offered the vegetarian menu from the MDR each night for more choice.
We tried the MDR one night to dine with friends. The food was ok but the service was way way slower than Blu.