I've always been a fan of point-and-click adventure games, and I'm happy to count this as one of the better examples of the genre.
Now, it's not perfect - however, some of my complaints are my own fault for skipping the tutorial.
Important tips to anyone starting off:
1) Double clicking on any 'arrow' location will warp Rufus to that location, which is great, since some of the maps are big, and Rufus doesn't run. (Figured out on my own ~1/2 of the way though the game)
2) Hitting space will highlight all interactive objects. (I never found this one out, and one of my complaints was going to be that some of the puzzles were a little pixel-hunter-esque.)
Generally, I found that the game was really superb for the first 2/3rds or so - the puzzles were just straightforward enough that you could figure out most of them through intuition or through the somewhat-subtle clues that characters would say when you tried the use the objects. I was able to make it through this entire section without having to hit the internet.
The final area, however, was definitely not as polished as the rest. Puzzles weren't nearly as clear, a lot more pixel-hunting (again, my own fault for not knowing about using space), and some of the solutions were much more "you have to know what drugs the creators were on when they thought this one up." I did have to hit the web a couple times for this part (stupid whale bait.)
The story was excellent throughout, and although the humor wasn't always up to Monkey Island standards, it was always enjoyable. Most of the voice work is good. Good cast of memorable characters.
I only ran into the most minor of errors - some graphical glitches where Rufus would, instead of walking to an object to interact with it, just reach out from where he was standing. No crashes or other problems.
Overall: A great purchase for any point-and-click adventure game lover.