As as been said, both are great boats! Here is another take on the pros / cons and different usages. We have a 44DB. The neighbor we share a finger with, great friends, have a 460 Sundancer. Huge beam, tons of space in the cockpit. On the other side of the 460 is another friend in a Jeanneau NC14, and beside them, more friends in a Meridian 490. All four boats offer something different.
When we are all rafted-up or at the dock in good weather, we typically all end up in the cockpit of the 460DA. If the weather is bad and there are just 3 or 4 couples, we tend to either be on our boat (together on the bridge, together in the salon, or spread out between the bridge, cockpit, and salon), in the indoor/outdoor open space of the NC14, or sometimes in the 490. If there are more than 8 people with visitors / kids, we can all fit in the large salon of the 490 and can all sit for dinner between the salon and the pilot house. During mosquito season at dusk, we all take cover in either our 44DB or the 490!
A 5th couple that is part of our group of friends had a Tiara C44 coupe, now sold. Another great boat and the way it was used was somewhere between the 460DA and the NC14. It had a great cockpit and a really cool countertop at the stern to hang out at.
My comparison for open water cruising is limited from experience. I can tell you there is no contest between the 44DB and the 300DA I had before, but not a fair comparison. I have been on pretty big water on Lake Ontario with the 44DB, and it is uneventful. It's also very comfortable and quiet.
My wife and I have lived and worked on the 44DB for weeks at a time and it is very easy to do. I don't think it would be as enjoyable in a Sundancer. I don't think I could go back to the canvas and eisenglass of a Sundancer (I would lean towards a coupe like the Tiara C44). That said, I envy the living space in the cockpit of a Sundancer and it is a better platform for a group to enjoy the water from.
Hopefully this is useful. Not trying to argue for or against either boat!