I really enjoyed the first film- it gave suspense and thrill on what would happen next, I also just liked the claustrophobic feeling. This movie was pretty decent enough, it gave off the same vibes as the last movie- suspense, gore, unpredictability.. but it wasn't as interesting considering that we knew what was down there now.
I was surprised when they found Juno in the cave, I thought she had died, and the ending was quite interesting as well, sort of like a cliff hanger.
I would recommend watching the part 2 because it gives you a completed ending and something to ponder towards at the end.