Before I got my 650 I had a Bonito 585profisher great alround boat, but a very wet boat have also heard that the 685 is a wet ride. If it is only 10k in it I would go the 650.
If you are going new boats I'd check your costs, you said in your other thead there was only 5k between the 600 and 650, there will be more like 20-25k difference. the 650 and the 660 will be closer in price around the 10k mark.
When I got mine new 2 years ago a 600sf all set up was around the 65k+ mark and the 650 was around the 90k mark.
How much is your budget?
If you are wanting to save a few bucks you might go back to the hh600 or look at a FI-GLASS WARRIOR at 6.4 I have read that these are a pretty good ride and good value for money.