The Field Book gives the advantages and disadvantages of various types of materials. Poly-weave tarpaulin floor material is often used in less expensive tents. It does not stand up nearly as well as nylon and is not found in better quality structures. You don't want to wake each morning in a shelter covered with condensation that will shower you at the least provocation. In better quality tents, some of the ventilation is provided by mosquito netting.
Poles are also a major consideration.
Many inexpensive tents have a poor grade aluminum alloy pole prone to collapse if bumped or if winds are high. Many tents, particularly domes and their variations, come with fibreglass poles. Hollow poles tend to be better than solid ones. Poorer quality tents often have ties or other closing devices instead, and these alternatives are all but useless in wind and rain. Ensure that zippers are of good quality and work smoothly.