The main thing with Sonny's, is that its in Brampton which doesn't seem to have anything worth noting for food when you go away from chain restaurants.
Lick's still has the best burgers in Brampton, and is better than Sonny's.
However, late at night when you're drunk is when Sonny's seems to be delicious. Realistically, its only because of the alcohol effect. When I used to live in Brampton, I thought this place was great but that was simply because it was all I knew. Now, it pales in comparison to similar "dives" when I look back.
Its also not a cheap place, and might actually even be more expensive than Licks.