As a high school student in the late 70's*, I saw this at the Uptown theatre in Mpls. in a 3D double feature with "Spacehunter: Adventures in the Forbidden Zone".
Having grown up with a love of the Universal Monsters from a weekly dose of "Horror Incorporated" on one of the local channels, it was great to see Creature in it's original 3D! Spacehunter barely registered with me; it was all about the Black Lagoon!.
*Edited post: Per a separate thread on the forum I now see that apparently Spacehunter came out in 1983, so I should have said, "As a college student home for a break in the early 80's..."
I do recall Spachunter glorifying in the "out of the screen and in your face" type of 3D, so it might be fun to see this released in blu-ray 3D at some point, but the plot, story etc. was less than memorable.
I see lot's of love on the site for "House of Wax" - it's on my "to buy" list - Vincent Price at his macabre best - I have only seen this in standard TV as a kid - again curtesy of "Horror Incorporated".