Re: Does it matter 2 u what
In terms of who to be friends with, it doesn't matter at all.
In terms of a spouse - I would marry neither a shia nor a sunni who has religious views different to my own. I would only marry someone with religious beliefs very similar to mine.
I believe that a marriage between a sunni and a shia would be religiously acceptable, but would involve tension in the same way that a marriage between 2 sunnis of differing fiqhs or other viewpoints would.