I've sold a few calculators to sellyourcalculators and a few to cash4calcs.
Comparing apples to apples the customer assistance from SYC is 10 x's better.
Sure I always want more money, don't we all... but good customer service out ways waiting weeks and weeks for a response as I experienced from C4C. If I had a question or concern I would either get a email or call the same day I asked it. Honestly, I have more calcs to sell and I know where I will be sending them because, SYC is faster and has better service. If you want more money, then deal with the BS and sell them on EBAY yourself.