Like any tent... its going to be determined by ventilation, location, size of shelter and weather, and like any shelter your going to have to deal with it.
Only thing is you only have 1 wall with them, so its easier to get wet.
Set up with the one open side I never got too much, with the annex you can get a good bit of condensation. This is in a little paratarp though.
I always carry a MSR pack towel with me (has oh so many uses for almost no weight) Ill use that to sponge off the walls in the morning if need be.
You can set these k tarps up so that they are so sealed up that you get almost no ventilation. Id suggest if your doing that to try to get a little air flow by opening a corner or whatever you need to.