I have extensive experience with Flysurfer Peak 4, Flysurfer Soul and several iterations of Clouds starting with the C2 and into the D's. I consider myself an advanced intermediate and foil exclusively now for 4 years. The answer is more about what you like to do. I love a kite that has exceptional drift. I loved the Clouds but got tired of carrying a pump. I sold most of them. If you like cruising fast the Soul is a great option. For me, I love the Peak 4. The are so easy to deal with for launching and landing (I'm almost entirely solo). You can hot launch them with safety anywhere. They are awesome, cheap and incredible for travel. I can pack my foil board, mast and wing, wetsuit, harness and 4 kites/bars in a check-in bag that weights 38 pounds! The Peak4 drift is insane and they only go into the water if the wind totally dies or you try to put them into the water. The easiest and safest kite I've ever used for solo launching and landing is the Peak4 by far. The souls have incredible water relaunch (Clouds too once you learn the method) but I still prefer the Peak4.
If I were more into speed and getting upwind the Soul is awesome. Put it this way: I bought a 6m, 10m and 15m Soul last year and sold all my D's. Then discovered the Peak 4. I started with the 5m Peak4 and solo launched in some insanely tight spots. I now have a 3m, 4m, 5m, 8m and 11m Peak4. I haven't used the Soul in over a year and I don't miss the Clouds. If you can lay the Peak4 kite out (on rocks, sand, pebbles, whatever, and undo your lines walking into the water, even swimming, launching is a breeze. You can always dump in into the water near shore in high winds but I've only done that a few times. They dry out in 2 seconds.
If I was exclusively drift launching the Peak 4's aren't good. I've had to swim a few times but I also had to swim with the Clouds. The Peak4 suck to self rescue as they sink and getting the water out is a challenge. Still worth using them and I kite all winter in the Boston area. Despite others that downplay the 8m and 11m Peak 4's I've used them. They are awesome and have allowed me to get on the water in very light winds. I bought the Soul's because I thought they could be good for both foil and TT (they are but I never do). The Peak 4 won't be good for TT. I wish I didn't buy the Souls now but I can't allow myself to sell them. Hope this helps.