devfee is another form of payment, and works both for small miner and big farm. Fixed price is only good for big farms, and lower income of small miners, who will not buy paid version since can not return investment back.
well, it's his choice, not yours. I haven't purchased any miners from him, there are plenty of free miners out there you can use, even without dev fee, but I don't come here and whine about the the price of his software. I understand sp_ completely - i do quotes for various projects every week. The work I do is far better than the shit competitors come up with and obviously it's more expensive. If someone don't like then tough luck - there are plenty of people out there who are willing to pay top dollar for decent work.