I also enjoyed this one. Rented the VHS from it at a mom and pop video store years back. I've been tempted to buy the DVD for a while, point in fact.
I like the design of the creatures, the main kid (probably the best kid lead I've seen in a horror film of this type). The pacing is also pretty solid, and the gore and effects work are very good for the films budget. According to the IMDB, the film's budget was $25,000.
A bit of trivia - I was looking on the IMDB, and a note there says Metamorphosis: The Alien Factor is an unofficial sequel. I've seen that film a couple times (have it on LaserDisc) and I never made the connection. But when you see the creature design, you can see the similarity.