I actually only had two of them hung up. The Serenity Vally one and the "Visit Tranquil Miranda" one. Mostly because I didn't have that much wall space and I had other things, like my Animal Farm poster that I wanted up as well. Someday I will frame more of them and hang them up. I really want to get the second set, there are some really cool ones in there, like Jaynestown.
I like how discreet they are. Unless you are familiar with the source, you'd never guess what they were from. One of my room mates at the time told me more than once how cool they were; he had no idea they were from some sci-fi show.
I think the poster set was $30 and I paid $9 dollars for each frame, so all in all, really not that expensive. Especially if you buy the poster pack then frame just the ones you want, or frame them one at a time to break up the cost.