Fortunately, the fourth season doesn't suffer from this problem. In my opinion, there are only two episodes that are even debatably great. "Pip", which really didn't have anything to do with anything,(It takes the South Park character, Pip, and places him in Dicken's "Great Expectations".) and "Helen Keller! The musical" which just plain wasn't a very funny episode.
These two are merely exceptions, however, as the remaining 15 episodes of the season are all really funny.
Moving in to the fourth season, the animation program used to create the show was changed, and so you'll notice that these episodes look more like a real animated cartoon than any of the previous seasons. For example, the "green rectangle" money is replaced scans of actual bills, and in general the show just plain looks better.
Again, Trey Parker and Matt Stone are throwing in their "Commentary-Minis". Fans hoping that they'll switch over to full length commentary are gonna be waiting for a while, as both Trey and Matt are opposed to the idea of listening to someone egotistically ramble about their own show for half an hour. I guess they don't realize that that's what some fans want. Oh well, at least its better than season one and two. (Season one came with CDs [available on comedycentral.com...for free, I think...] that you had to rig up to play at the same time as the episodes on your DVD player for the commentary...And there was a LOT of awkward silence. And season two didn't come with any commentary at all.)
Well, I definately recommend that any fan of the show, regardless of how many episodes you've seen, pick up this set.
The fifth season on the other hand....well that's a whole 'nother review...
Anyway, I hope this review was helpful to anyone "on the fence", deciding whether or not to pick this up.
Below is a list of the episodes in Season 4 and when they aired.
5-Apr-00 The Tooth Fairy's TATS 2000
12-Apr-00 Cartman's Silly Hate Crime 2000
19-Apr-00 Timmy! 2000
26-Apr-00 Quintuplets 2000
21-Jun-00 Cartman Joins NAMBLA
28-Jun-00 Cherokee Hair Tampons
5-Jul-00 Chef Goes Nanners
12-Jul-00 Something You Can Do With Your Finger (a.k.a. Fingerbang)
19-Jul-00 Do the Handicapped Go to Hell? (1)
26-Jul-00 Probably (2)
8-Nov-00 4th Grade
15-Nov-00 Trapper Keeper
22-Nov-00 Helen Keller! The Musical
29-Nov-00 Great Expectations
6-Dec-00 Fat Camp
13-Dec-00 The Wacky Molestation Adventure
20-Dec-00 A Very Crappy Christmas