I have tried Ancestry (library) and Findmypast (library and paid). They both pay for archives to digitise some of their holdings. Forget details, Both has things other doesn't but think Ancestry is ahead.
I found the search facility frustrating - you needed to play with options a lot.
My dad did research before these sites existed which was harder work but more fun. I recall instances where Ancestry made wrong assumptions (something like mire than one John and Joan Walker in same town).