We're booked on an SV early next year on the Silhouette. When we booked, I think it was about $500 pp more than Aqua class. For the refuge of the Retreat Deck, Lounge, flexible embarkation, and smaller dining experience in Luminae (and possible Blu) we were willing to pay it. Not sure I'd do it for $2000.
It's all about what's important to you. On the bigger Ascent, you may want that space the Retreat areas provide to get away from the crowds once in awhile.