Goenka has spread a form of vipassana worldwide. With a veritable factory mindset, they provide a cheap and intense meditation retreat if you are willing to put up with their extensive level of control. I recently came across a description of a first timer at a Goenka retreat, "The Quiet Hell of Extreme Meditation."
I was struck by the insanity of traveling to India for a retreat that could be had almost identically anywhere in the world, and as always, by the pain experienced. Sitting on the floor is a remnant of a society that didn't have chairs. We have chairs today. If you're complaining about knee or back pain at a retreat nowadays, I have some sympathy, but mainly concern for your dogmatic views about sitting. We need to get beyond the idea that there is something magic about sitting on the floor.
A comparison of Mahasi and Goenka:
Goenka Pros: Slow body scanning is nonverbal and continuous, I like both of those characteristics. I have a sense that for many verbal westerners, this may be a good entry into the meditative world and combined with the intense retreat setting may be one of the biggest generators of a big initial "awakening", the experience referred to as the Arising and Passing. If you get one of those big experiences, you are more likely to keep going.
Goenka Cons: The scanning is dogmatic movement, head to toe and back, so at least as defined it doesn't allow for jumping to areas that might need immediate attention. The focus is only on the body, while there is tremendous insight value to be had from attending to emotions, mind states and thoughts.
Mahasi Pros: Noting covers all possible experience and allows one to focus on what is predominate in consciousness at every moment. Noting interrupts thought and begins to break up one's experience into the original building blocks. Noting directly points out what Buddhists refer to as Dependent Origination, an important insight.
Mahasi Cons: Mental noting is verbal, which may not be ideal, although it is kind of like taking the typical mind's strength and using it against itself. Noting requires a bit of vocabulary and has a longer learning curve. Beginners typically don't like it, preferring something like following the breath or a mantra.
It should be said that even many of the teachers who do not favor a hard core, once per second noting style like Mahasi, tend to acknowledge its relatively high rate of success at getting students to stream entry, 1st path. Indeed, some have referred to the Mahasi Center in Burma as a stream entry factory. I've never heard that said of IMS or Goenka. I do hear about people having a big initial experience on a Goenka retreat, but I don't hear much about further progress. This could be due to ignorance, one reason I recently posted a few things about stream entry.
Anything that one does to stay aware and present and relaxed is likely to help, and clearly people awaken with different methods. My bias is to Mahasi, what can I say, it worked for me.