If you are familiar with the original series, and love it, be prepared for disappointment. Being a huge fan of the original "Spider" series (both my sons absolutely loved the video when they were small - now both in their teens), I purchased the singalong dvd for my youngest son (age 2), hoping that it would replace the old VHS Spider series. Unfortunately, the singalong dvd only covers half of the original songs, and misses out five songs, including several of my son's favourites. The dvd only plays for 28mins as opposed to the original almost 1hr.
Also, the illustrations have been a little modified (spoiled), by adding too much colour and thickening the black outlines on the figures (spider's legs were never that fat!!)
However, it does have some fun links between the songs. Being given a voice (never had one in the original), the boy introduces each song, awaiting his spider friend to help him. Spider keeps popping up when the boy isn't looking. My son loved these, pantomime "he's beHIND you!" bits.
In short, I'd recommend you get the original: children will learn the words to each song without them printed on screen (and these flash up in quite a crude, amateur karaoke way); they'll have the benefit of ALL the songs, not just half of them; and the original dvd is actually cheaper (yes, the singalong dvd is more expensive too!).