The job of a tent is to simulate a good cave. It is, in effect, our portable cave. As such, it needs to have several characteristics. Few tents have all these characteristics. Many have glitz that would do a Barbie fan proud, but leave them cold and wet.
1. Shed precipitation - this means it must have OVERHANG. Awnings over windows MUST stick out way beyond the drip line so wind won't be able to blow drizzle and mist in through an open window. Awnings MUST hang out over a door so that entry and exit in a rain storm does not admit rain. Dapper Al has a Coleman tent to which he added two feet of overhang all the way around. It is now a good tent, before it wasn't. On the outside, the storm fly should be sufficiently sloped so that snow will slide off rather than sink in.
2. Provide ventilation - this means that air must be able to enter, pass through, and exit freely. Windows and doors should be available on all four sides. They should be screened, and open from the top downwards. Air should be able to flow without water coming along with it. Refer back to characteristic# 1. BTW, many attachable vestibules block ventilation. Sometimes, you can compare two similar tents, one larger than the4 other, that costs and weighs about the same as the smaller tent with vestibule. I give the nod to the larger tent.
3. Stay put - In strong wind, the tent should stay put. Most tents have tie downs, but not enough of them. Add tie downs to the frame before you add them to the fly. Stake out the fly for improved ventilation; stake down the frame to keep the tent. Have more guy lines than you think you need.
4. Stay dry inside - Every year, reapply sealant (deck sealant and a brush do an excellent job, you can waterproof your maps the same way) to the seams of the tent and fly - ALL of the seams. Add an additional liner. There is controversy here about whether to add it outside under the floor, or inside on top of the floor. It's according to what you are trying to protect. If you are protecting the floor, then outside in between the tent floor and rocks, will do that. If you re protecting yourself, then inside will do a better job. Measure the floor, add 12" to both the length and width. Get a piece of visqueen of that size (or larger and trim it to size). Fold and tape the corners so you have a bathtub with 6" sides. This will keep out water even when the floor leaks.
5. Light weight - This is a balancing act. It is much more important for backpacking than in a boat. In a kayak, bulk is more important a consideration than is weight. That kind of reverses in a canoe.
6. Convenient entry and exit - To me, this means two doors. If there are two people in a tent, the second door will be as handy as a pocket on a shirt or zipper in our pants.
7. Cost - This is the least important consideration. You can either pat yourself on the back once when buying a cheap tent, and kick yourself int he arse every time you use it - or, you can kick yourself once when shelling out extra bucks for the one you really want and pat yourself on the back several hundred times later. Your choice. (I suppose it's possible to find the best tent costing less, but I wouldn't hold my breath.)
When all's said and done, I'd start with a tent that has been around for a long time, and has proven itself. My thought line runs to the Eureka Timberline as a starting point. Compare all other candidates to it, and reject anything that cannot match it on any single criteria. If you find a tent that matches all criteria, don't reject it. If you find a tent that matches all, and exceeds some, use it as your new standard and keep on evaluating other tents.
I hope this helps.