I've had these wings for about a month now and have tested them in a wide variety of conditions. From light winds on flat water, medium winds with 1m choppy waves, to strong winds with 2m swells.
I previously owned the 799, 899, and 999 wings since they came out, so I've been using them for years and have had them handy for all kinds of conditions. I compare the 808 to the 799, the 909 to the 899, and the 969 to the 999.
All three new wings have similar takeoff to the old wings. The 808 and 909 need a bit more speed before you can pump the foil. The 969 can be easily pumped at low speeds. Once the board has taken off, the difference with its older versions is that the new wings are much faster, more agile, and more maneuverable. With each of these new wings, it seems like there's much more wind than with the old ones. With the same effort as before, you can ride upwind at a much tighter angle, so you gain a lot of windward easily. The downwind is much better than with the old wings. These new wings, apart from being faster, have much more glide, so the experience changes significantly.
I'm using the 370 stabilizer for all three wings.

I haven't tried them but, from what I've been able to find out, I think they differ in that the Balz pro have greater glide than the Medusa pro

As you say, with the 103 I can't change the foil position and since the 999 is slower than the others and causes the nose to drop,
I put a positive shim of 1? to generate lift, nothing for the 899 and a negative 0.5? on the 799 to reduce some lift. This way I had balanced the supports of the rear and front foot regardless of which wing I used.

Everyone's perceptions are very subjective, but keep in mind that I've compared each of the Balz Pros to what I consider their equivalent to the older ones:
999>969
899>909
799>808
As I mentioned before, I've used the older wings for years and many sessions (luckily, I can foil more than 200 days a year) and I've always enjoyed them, so I really liked them and wouldn't part with them without thoroughly testing the new ones.
To be sure, I did a test ride with each of the wings.
First, I used each of the new wings to adjust their lift, and then I practiced with each one for several days to learn the technique needed to enjoy them.
Then, depending on the forecast, I prepared a full foil with a Balz Pro wing and another full foil with its older equivalent wing. With the Kraken system, I could change the entire foil in seconds, so I would put one foil on the board and the other on the car parked about 30 meters from the shore. This way, I could get out of the water every 25 minutes to quickly change the foil and test both wings in the same wind and sea conditions, with the same sail and board.
After all this work, my subjective opinion is that the Balz Pros are more in line with my tastes.
After such good times, I was very attached to my beloved old wings and it was hard to let go of them, especially the 799, which was the one I liked the most.

Grantmac said..
I recently picked up a 909/370 combo I have yet to get wet. I got it for winging but I'm curious about potentially wingfoiling using a 903k fuselage in flat water/light wind (winging really isn't fun with a big wing).
I look forward to see how it rides since reviews seem very positive.

It is my go to wing for all conditions 10-30 knots on windfoil with 903k fuse and 395 stab. Sails 5.2-3.3. Have the Medusa Pro 769 for those special 25 knot+ days in bigger faster swell.

I've only run the 769 medusa, but the dynamic range is pretty incredible for such a small surface area IMO. I use it in 18-30+ knots. Whats surprising is how low the stall speed can be with the right tail (SS 360 vtail) in my case.

Mr Keen said..

WsurfAustin said..
I've only run the 769 medusa, but the dynamic range is pretty incredible for such a small surface area IMO. I use it in 18-30+ knots. Whats surprising is how low the stall speed can be with the right tail (SS 360 vtail) in my case.

I agree, but find it a little quick to get endless rides on large slow short period wind swell. The 769 comes alive on flatish water or open ocean large long period swell where speed is an advantage. IMHO

Ya, that makes sense. No such conditions here, so speed it is..