It all comes down to whoever was around when you first got in to music. If you got into The Smiths at age 16 or so, then you were probably to young to appreciate The Jam, or indeed the influence that they had on Morrissey & Marr.
As someone who brought, and still plays on vinyl everything the two bands produced, as well as seeing both live, there is only one winner and that's The Jam by a comfortable margin.
Prince Monululu has already posted Marr on stage with Weller, and here is Morrissey destroying That's Entertainment.
Some people just don't get it, well explained.
There is a couple or at least one post in another round of this competition with a list of hits by The Jam in the 70s and 80s, I'm sure they had higher chart positions in the 80s.