Thank you for both articles, once read, buying a tent suddenly becomes more difficult.
In my case, when camping with my tarp, I'm using the bathtub floor from my old Zephros One tent on top of my ground sheet and under my mattress, it's light, rolls up small, it's strong and I think it keeps the ground wetness at bay very well.
I only have experience of three tents and I would not use any of them without a groundsheet or footprint, or both. I'm now looking to buy or to get some Tyvek to replace my groundsheet, it seems to be recommended by many as the groundsheet material of choice.