I've riden the Naish 9'6" a couple of times - it's a great board. You can read a full review I've done here: www.CyberSUP.com

I've never riden the Bonga 10'0".

I've paddled both, and they're both awesome,

If I had to make a choice, I'm not sure what I'd do

the naish is more stable and the bonga paddles faster.

On the Bonga I don't like the deck pad as I find it slippery (I actually need to wax it), I like the shape, narrow longboard, noseridable, don't turn as tight as the naish but much better than some other "shortboard style" boards, the rails are working really good in hollow sections when you're looking for some cover up .

The Naish compared to the Bonga turns tighter, you can walk towards the nose but not really noseride it, the quad fins are perfect to climb up the foam and easy to ride, the bonga is harder to ride from the tail but once you find the sweet spots I find it slashier than the naish on top turns, after a cut back the naish gets ready for next move quicker than the bonga..;
The Bonga is a very good allrounder working good in any conditions for someone who likes mixing styles
The naish is a radical board for those who don't wax the nose of their board and want to through buckets of water in every wave they catch.

this is my opinion

regards,

Eric