You talking the new bongas or the old brown deck bonga ?
If its the old bonga then they are probably the tippiest damn board on the planet.
If its the new bonga then I have tried the 10.6 and the 9.6. I weigh 75kg and am intermediate level sup surfer. The 10.6 was hands down the worst sup I have ever paddled or surfed and I could only tolerate it for half and hour and had to come in. It was a pig to paddle and felt very heavy in the water and didnt turn at all well in the flat or in the surf. Also very prone to nosedive due to the very heavy forward section.
The 9.6 however was a really nice board to paddle and surf and I spent a few hours surfing it in waist high beachies and had a blast. It is still a little nose heavy in the surf but once you get that wired you don't tend to nosedive it too often. Its stable and a reasonable paddler and turns really nicely and with minimal effort on the wave.
I have surfed the old bonga and have to say that it is soooooo outdated and such a bloody tippy board that they aren't worth buying at any price. IMO