Neverwinter is a decent effort. If you've played Star Trek Online, you'll notice a lot of similarities in how certain things are setup. But it will be a change if you haven't played an action type MMO where you are not specifically selecting your target by clicking or with the Tab key. Instead, you're hovering the reticle over your target and using your skills to attack or heal, etc. The graphics are on the low end, especially if you look at raw texture resolution and detail, but they do a good job with what they've got and the aesthetics are nice.
I think the biggest boon to the game will be The Foundry, which is a very polished and powerful way for players to create their own content. It's entirely possible (and has already been done) for people to create multi adventure arcs full of good writing and story telling. If you're into the creation side of things, The Foundry is a fantastic thing. And of course it offers a lot of variety for players to see new content and stories.
It wouldn't ever be a "main" MMO for me, but it's a nice diversion. And it's easy to sit down and accomplish plenty in an hour or two, so it doesn't have to be a huge time sink. Things like crafting (which can happen while you're offline, sorta like The Old Republic) can also be done from a web interface without the need to log into the game itself.
Edit - Oh, and even though they insist on calling Neverwinter an Open Beta right now, it's really a soft launch. There are no character wipes going forward, so if you play and happen to like it, you won't lose anything once the full launch comes around.
