A two man tent is a one man tent, 4 person is a 2 person, and so on. Look at the diagrams. The tents shows 4 people jammed together tightly. Try and get up to pee at night and your going to step on somebody.
If you need a true 4 man tent, you going to need a 6 man. Look at the temps, weather, terrain, and time of year your going to use the tent in. Pick the worst of each and then post some specifics here and you will get a clearer answer.
I have been camping and hunting in the high Cascade Mountains my entire life. I use North Face Tents. They are not cheap. They also never fail me. I have used the same 2 man tent for hunting, high mountain traversing and camping alone or in small groups for 20 years. Rain, hail, sleet, heavy snow, high winds, it stands up to it all. It is one of the bright orange tents you see on Discovery Channel on the side of Mt Everest.
Getting the right tent is a decision to take very seriously. Buy the best tent you can afford.