When it comes to tent size you should almost always consider a tent that can sleep more people than you actually need since space is usually exaggerated by the different tent brands.  Thus, if you are looking for a 6 man tent you should probably go with an 8 man tent just to play it safe, especially if you are bringing an air mattress or a lot of camping gear. 

6 man tents can be perfect as a 4 man tent and will provide you some extra room to feel more comfortable in. 

Coleman Sundome 6 Tent-

This 2 room affordable tent by Coleman has a center height of six feet and comes with a  12×10 rainfly. This tent is normally a screened tent so unless you have the rain fly on you aren’t going to get any protection. This is a great tent for beginners as it is easy to set up with its color coded tent poles.  Unlike most tents this one comes with an integrated light system!!  I think that has to be its main selling point.  It is a light that is good enough to be able to read while you’re in your tent at night and is controlled with a remote control that can be used up to fifty feet away.  A battery pack allows for up to 16 hours of light usage on low or 12-14 when powered high.  It also comes with negative angle windows that allow you to keep the windows partially down even if it is raining.

Coleman Montana 6 Tent-

This tent is an inexpensive family tent that won’t provide very much standing room.  It is also a little sparse on interior space so if you have 6 people all of you might not be able to fit into it comfortably and your gear certainly won’t.  It is very easy to set up and comes with a tent rain fly.  However, you might want to be extra careful as some users have found it to be inadequate in keeping the rain out.  Overall, it’s a tent that will work well if you know you will be camping somewhere it’s dry and conditions are mild.  It is definitely a 3 season tent.

Coleman Evanston 6 Tent-

This is another Coleman tent that is great for beginning campers.  However, it probably won’t let you sleep up to 6 people.  It’s probably better used as a 4 man tent.  It is extremely set up with just 2 fiberglass tent poles.  Unfortunately this doesn’t come with the tent light that the Coleman Sundome one has.  The fabric is a little thin though so you will need to be careful when pushing the tent poles through so that you don’t tear it at all. 

Kelty Yellowstone 6 Person Tent-

Every company that makes tents seems to have their own patented design to keep out water seepage.  Kelty is similar and this tent is made with the ArcEdge design to help any water from getting into your tent.  This system raises the tent floor up a little bit off the ground which helps the water not get inside through the floor and the seams where the walls meet.
This tent also comes with a lot of other features like interior pockets for storage, color coded tent poles, external guy points to help when you are camping in windy conditions and noiseless zipper pulls.  The noiseless zipper I think is a great benefit for a light sleeper.  As with most of the tents this 3 season tents space might be exaggerated when it comes to the amount of sleepers it fits, so you might want to just use it as a 4 man or 5 man tent.  This tents weight is about 17 pounds.

Cabela’s Westwind Deluxe Tent-

This tent is free standing design that utilizes 5 shock-corded fiberglass tent poles as its frame.  It is made of nylon taffeta and its seams are hot taped to prevent leakage from any rain you might face.  It has more vestibules to protect your gear better and multiple guy out points for stability in the wind.  Like the Kelty Yellowstone the size that sleeps 6 people weighs about 17 pounds.  But you can also purchase it in two other sizes to sleep 4 or 8 people, so if you need space for 6 people consider getting the 8 man tent.