4" backsplash is a dated look. It means your backsplash won't meet your counter, but backsplash meeting counter looks much better. The 4" backsplash will, however, make an easier job for the counter fabricator, as he won't have to scribe as carefully since the 4" backsplash will cover any irregularities in the wall. Though if so many counters can look nice and not have the 4" backsplash, I don't see why they all can't.