Would have to be mayo then as would struggle to eat chips, fish finger sarnies and several other things without it. Don't use much salad cream at all these days but it is just FANTASTIC on a pork pie.
I don't really like either particularly, but mayonnaise edges it just slightly because I like tuna mayonnaise and egg mayonnaise, those two things with salad cream instead of mayonnaise are ****ing discusting .
There could be an age thing with it. Im in the salad cream camp, but when I was growing up, there was no such thing as mayo. That was for Europeans, and posh people so only ever had SC growing up.
Mayo every time (although my mother would completely disagree as she has been previously caught in the kitchen with a bottle of salad cream and a large table spoon).