I had a M659 ABS in a few weeks ago to fit a power kit to. The owner had bought a M696 ABS Ducati Performance kit from Germany, which he hoped (and I figured) would probably be pretty close. The difference between the two engine wise is a shorter stroke crank and (I expect) a longer piston. I haven't had a look at the parts catalogue yet to confirm it. Chassis wise I believe there is no difference.
However, on the day we found the kit was complete except for the little brackets that bolt to the mufflers and the frame. But I did fit the air filter and lid and the ecu. Checking the throttle opening via the diagnostics when doing a TPS set I saw that maximum throttle was 40 degrees. M696 show 79 or 80 degrees at WOT (and 0 at closed throttle) in my experience, so it's getting almost half the normal throttle opening.
When I rode it though (std mufflers still) I was quite amazed at how well it went for a LAMS bike. While I have always had quite strong feelings about the inappropriateness of most 250s in terms of getting out of harms way (back in my day a CB250N was the norm and as much of a slug as any of the 250cc 4 stroke twins on offer) I was still surprised at how much performance the learner was getting from the 659. The owner did say that it went quite a bit better with the ecu and air filter kit fitted, but I don't recall what he said about the impact the mufflers had when he finally got them on.
I did ride a 696 a little later, which put some perspective on the 659. I haven't dynod a 696, but I would say they would go as well as my hot 750 once you get the revs up. Certainly a nice little bike for getting around on. I was discussing the 659 with Bob at Ducati City, who have sold quite a lot of them. Even to non LAMS requirement riders who just commute. The main point there is resale. A LAMS bike version will have much better resale than a non LAMS, and if you don't need the power there's no point having it.
As an indicative comparison, this is a dyno graph of a 750SSie I mapped years ago. The red run is full throttle, the blue run is 40 degrees. As you can see, similar power output under 4,000 rpm and about 2/3 of the maximum at its peak. I expect a 659 vs 696 graph would look much the same, although the 659 should have more top end bias I expect simply due to its larger valves. They're a bit bigger than the old 900.