I'm big on skyblocks. Of the packs I have played and documented (see signature), most have been skyblocks. Most have also been packs with a challenge involved in them. Sometimes it's both. For me it started with having a rather slow computer when minecraft and I first met. If I had to render an entire world, my computer wasn't as happy. If I played on a skyblock things worked better.
Lets just say, the challenges are different in a skyblock. You don't face random mob spawns, but if you do make a mistake and mobs show up where you don't want them, things get hectic rather rapidly. You don't spend hours doing strip mines, you spend them sitting at sieves, or building machines that run sieves for you, or cobble gens, or bees, whatever the mechanic of the pack is.
A new pace, a new way of life, things are not the same. Not better, not worse. It also lets those who make the packs have slightly more control in making the world and building the challenges.
I'll do my best to explain any of the broken stories that don't have pictures up and set you up with links to the right photobucket folders, feel free to ask questions (and drop likes*cough*).