Pro (compared to SU):
1) There's only one of them.
2) Slightly better economy if driven for that (and only if).
3) Once tuned, stays in tune forever (good SUs only stay nearly forever).

Con (compared to SU):
1) Fine for a mild motor, but won't support as much power as SUs.
2) Much more complicated to tune, if you need to tune it.
3) Tends to ice up internally on foggy mornings.

A new Weber is much better than worn out SUs. A worn-out Weber is at least as bad as worn out SUs.

Your call.