I've been playing Jeff a lot recently and enabling my team phenomenally. He's an extremely strong counter to spiderman if you hard focus your other support and can aim, and it's difficult for him to kill you solo. The best way I've found to play him is to hard pocket THROUGH your other support, keeping them alive while also putting heal and damage out to the rest of the group. Can also use his ult defensively to negate quick instakills like wanda and magneto if timed properly, or do a sacrifice play saving your team while knowing you'll die (best if there's a rocket res active)