Vinegar is acetic acid and water (7% acetic acid diluted with 93% water) so it doesn't really matter, you can always balance your sauce with more water or add more vinegar etc. depending on how you like it. Once you figure out what works best for you go for that.
Some people work with 100% acetic acid and dilute it themselves.
What you can do is figure out the type of vinegar you like best. That is more important.