I was thinking of doing a video actually. The 1 million cycle minimum switches have a definitively audible click sound, though slightly different than the original. It's more of a "solid" sound? I will put both in side by side for comparison.
The 10 million minimum cycle switches are essentially inaudible. While playing you'd certainly not hear it. You can only hear them when not playing and actually trying to hear it. Some people actually prefer this apparently... Which is why I mentioned it here. As well, you cannot feel them click. They engage quickly upon pulling the paddles.
I used the lighter, stealthier ones this evening for quite awhile when testing and they worked really well. I liked the immediate nature of the switch as opposed to the original which engaged a bit later due to the added force necessary to activate it.
As for the originals... I don't have the model of them as they aren't marked, at least not that I can see. However, I did compare them this evening to the 1 million cycle switches. The 1 million cycle switches required right around 20 grams less force, depending on the original switch I tested. (I tested a few) I believe the switches I purchased are a direct replacement, though higher quality. They are sealed, dust proof, etc.
The switches that were chosen are made my Omron and are about as good as it gets for something like this. After doing some research it looks as though as a general rule, switches that require the same force as the originals and the 1 million cycle Omron switches, only have a minimum of 50k to 100k cycles. Given how often the switches seem to go and how quickly, I have to assume it's closer to 50K for the stock ones. Kind of sad really.
In "closing" I personally think the 1 million cycle switches would last as long as someone felt like using them. I'm inclined to go with them instead of the higher 3 million or 10 million only because they behave almost identically to the stock switches. However, it's not just up to me.

I asked here and I'm speaking with John about it as well.
Edit: Just to add... I have to wonder if part of the issue with the original switches is the force being placed on the switch. The spring that is pressing on the switch is really quite strong. If the original switches are not very high quality to begin with, this could degrade them even quicker. That is purely an assumption on my part. However, it could easily play a role in their rapid deterioration.