I have bought plugins from a majority of developers here in the Oxwall store. My opinion of most of their work is, at best, "just ok, sometimes quite amateur, not well-thought out".
But virtually every plugin I have bought from Sergey Kambalin I find to be far more well-thought-out, light on load, highly professional, and every plugin I have bought from Sergay has WORKED PERFECTLY RIGHT OUT OF THE BOX. Sergey's development skill seem to me to be far more advanced than most of the developers here.
I feel very confident now in buying his plugins. I hope he continues to develop more plugins. I think his price is fair, because he has more skill, and I don't feel I'm taking a risk buying his plugins. Because when I buy a plugin, I want it to work right away. And that is exactly what happens when I buy Sergey's plugins.
I don't want to have to wait for a developer to come and screw around with my site trying to fix what he should have fully tested and fixed before putting his plugin up for sale here. There's nothing more inconvenient and hair-pull-frustrating than having to wait and figure out what's wrong with a plugin you paid money for. I find that HIGHLY UNPROFESSIONAL, IRRESPONSIBLE, UNRELIABLE, and just plain inconvenient.
Sergey, please keep developing great and professional and reliable functioning plugins. I find them to be worth every penny you charge, simply because they are clean, integrate perfectly, and work instantly out of the box.