Hola Alyssa,

using this sentence:

is less formal than saying:

in the sense that the second is the most "standard, formal and literal" way to say it, and the first one using "estamos a" would be more informal and idiomatic. 

But both can be said in any context and situation. You could use both when talking to a friend, and you could say both when you are in a more formal/serious situation, e.g. a meeting with clients.

I hope this helps,

Saludos,

Inma