I saw "The Muppet Movie" first, at the movies. Having been born in 1974, I always think I grew up in the best of times when it came to movies.... I got to see the Muppets, the original three Star Wars movies, and all three Indiana Jones movies on the big screen.
I then saw the "Great Muppet Caper" at the theater a few years later, but it was a big disappointment. I don't really know if it was such a bad film, but I loved the original so much that I was inevitably going to be let down by anything else. I guess my expectations were too high.
I didn't see any of the other Muppet films until much later. I think I saw "Muppets Take Manhattan" on TV, and thought it was okay, but still not quite up to the level of the original. I watched a bit of "Muppet Treasure Island," but I hated it and turned it off after just 45 minutes. "Muppet Christmas Carol" was a bit better. The last one I saw was "Very Merry Muppet Christmas Movie," which was okay, but I can't help thinking Henson would have done it better. I still haven't seen "Muppets From Space."