Any tent with a 3 dollar tube of seam sealer will keep you dry in the rain. Any tent on a clear night with the tarp off will act just like an expensive tent. The difference I have found, the quality of the poles is better on a expensive tent, it will "generally" weigh less, come with much better stakes, but most important, it will withstand winds much better.
I generally use a 7x5 Coleman tent now. It's a tank to carry around but it also acts like one. I previously used a good quality bivy tent which did the job well but I wanted more space.