I actually have a few of them! Voyager, the Delta Flyer, the Val Jean, and a Borg cube. The NX-01 and Defiant are in the mail. While I love the novelty of having and building my own fleet, the quality of the bricks I feel could be better.

Don't get me wrong, it isn't bad, just not nearly as good as Lego. I've had to in several situations glue down pieces since they won't stay in place. One angled board I received had a chunk of it melted away. That type of thing.

You will have to press harder than you think you should to get larger bricks to stick together as well. Again, not a large problem, but it can be annoying (you might make your fingers sore as a result, I've had to take breaks because my fingers just needed to recover).

Last thing, you will absolutely get sick of the color gray. So. Much. Gray. But, I still think they're worth it, the novelty of the sets makes them cool to build and they still are fun, they just have a few shortcomings as it isn't as quality as Lego.