I know you can become a werewolf by finishing the companions quests, but is anything effected if you do? I know in werewolf form you don't wear any armor, but when you go back to human is that armor lost or still equipped? Are there any quests you can't do or any people you can't talk to you? I heard when your a vampire some people won't talk to you and they'll attack you, so sometimes you can't finish quests, can that happen when your a werewolf?

When you revert from werewolf form, the armor that you were wearing beforehand is unequipped and can be found in your inventory.

While in human form, people will not recognize you as a werewolf and as such no quests are affected. They will only attack if they see you transform (1000 bounty too) or if they see you in werewolf form. However, any crimes committed in werewolf form (ie murder) do not result in bounty if no one saw you transform, as no one will recognize you.

Basically, being a werewolf doesn't have any ill side effects besides the loss of the sleeping bonuses.
I hope that answered your question.

You can't go to sovengarde when you die if you are a werewolf. I think at least.

Your armor is only unequipped after your transformation.

You get a bounty if seen while transforming.

No quests are locked if your are a Werewolf.

You get a little extra dialouge with one member of the Dark Brotherhood.

There is a bonus for Werewolves on Solsthiem.

Everything is unequipped when you become a werewolf. For example, if you are wearing full daedric armor when you transform, it will be put back in your inventory and you will have to reequip everything when you finally revert form. The only time in which people will know that you are a werewolf is when you transform, so there are no penalties to becoming one in regards to quests. If you were to become a vampire, then the only time in which npcs will know will be when you reach stage 4 by not feeding at all. However, this was changed in Dawnguard and if you have it, there will be no penalties to quests whatsoever.

That is not true. You can use Illusion to cast Calm and complete any quest, no matter if the NPCs are aggressive.

I know you are not asking about Vampires, but I wanted to clear that up for you.