Tents which require liquid sealant on the exterior will not remain waterproof, because the sealant will peel off the fabric due to the teflon or silicone water repellent treatment. Tents with interior binding tape seams will be nearly impossible to seal on the inside. Flat felled seams are strong, but difficult to seal, with two rows of exposed stitches. We do not use cotton wrapped thread that can rot and fail. In a Bibler Tent the seams are never a weak point.
Condensation is something to be concerned about when looking for a new tent.
These fabrics do not breathe enough to prevent condensation, they are merely cheaper. Remember that ventilation alone will not prevent condensation, as you know if you have ever camped under a suspended tarp, open on all sides. On double wall tents, look for panels of coated fabric, high coated side walls, or coated fabric doors, which always bead up with condensation. Full coverage rain flys often have heavy condensation, because there is no way to ventilate in poor weather. Look for awnings over the doors that can stay unzipped a little in the rain.