Is it best to stick together or spread out in MW3 team deathmatch?

This question regards to which method is more effective in winning matches, not necessarily gaining experience or proficiency. Usually, my first instinct tells me that I should always stay close to my teammates in multiplayer shooters. However given how easy it is to die, and how fast it is to respawn, is my instinct still correct?

I'm starting to feel like there's not much advantage to sticking together. And spreading apart at least makes you less vulnerable to explosive damage. Which course of action gives your team the best chance of winning?

Keeping a group together, but reasonably well spread out helps to protect you from an experienced enemy team. Keep in visual range in order to be able to provide covering fire, and use your role strengths.

If you are close together, you can lose 2 or 3 people before you can get to cover (the enemy can concentrate their fire and move rapidly from one target to the next) whereas if you keep a looser group you are harder to 'box', less susceptible to a well placed grenade taking out more than one, and force an enemy to have to spread out more.

This looser unit requires very good comms to work well.

Sticking together works well if you have a team that communicates well. You can form a nice rolling mob and clear out rooms, campers and snipers and overwhelm other groups. You can split up and flank opponents. It is also much easier to hold a position if you have a well co-ordinated team. If anyone dies you can quickly inform your team members where the kill shot came from.

Your point about explosives only really applies if you are riding each other, if you keep a reasonable distance explosives shouldn't bother you too much.

From a strategic standpoint, it makes sense to split up into smaller groups. In the regular TDM, 3 groups of 2 makes sense. As stated before, this allows you to not take damage as an entire unit and also allows for teams to cover angles across objectives with other groups of their team (imagine a cross with the objective at the center of the cross and the groups sight lines being the axes of the cross).