We've been regular cruisers on Crystal but decided to give Oceania a try because many people told us it was equivalent, and with better food.
The food was perhaps a tad better but everything else was much worse. Especially the (lack of) quality on-board entertainment. The Master of Ceremonies was okay but the dancers/singers and other acts were way below Crystal's standards.
Their version of 'The Bistro' was a tiny coffee counter with almost no seating. Very uninviting.