I bought Nelo 520 couple of days ago and today was the day of the first paddle, ~6-7km in totally flat and calm water.
I'm total beginner and the boat was joy to paddle, super stable, felt fast, very responsive to steering input (I used short polycarbonate weedless rudder), de-brito bailer worked like a charm.
I can compare the boat to another beginner surf-ski I tried as well this summer (Vajda Oscar) and while it's fine boat for sure, it felt little bit too stable, voluminous, unwieldy, eq "Barge-like" feeling, while Nelo 520 is little bit more twitchy (less primary stability, still plenty of and rock solid secondary stability), but much more responsive and lively (much lighter as well, 13kgs vs probably 18kg Vajda Oscar - heavy fiberglass club version).
I also tried Vajda Hawx elite ski, but that was just struggle to stay upright, I couldn't put any real power into the stroke.
There are just 2 small things which I'm little bit unhappy about:
1. Weight, the ski (WWR layup) is advertised as 12,5kg, while it's 13kg in reality - that's ready to go with waterproof phone holder on go-pro mount and slightly heavier polycarbonate weedless rudder, without the phone holder and with ligther carbon surf rudder, it would be probably 12,7kg, so closer to the advertised weight
2. While the plastic line adjusters are great and super easy to use, they rub the inside of the footwell with any steering input, as they are hard plastic with sharper edges, I'm little bit concerned that over the time, they will scratch/wear down the polyurethane topcoat, so I will probably put strips of black electrical tape there to protect the topcoat.
Other then that, all is good and I really appreciate the shorter length of the ski, as I have to store it inside my apartment and it's lot more manageable then something over 6m