3d max isn't fundamental in 3d industry, it doesn't determines sale success, what determines number of sales is the quality of the model itself, it doesn't matter in wich software it's done. I never comment/rate other artists work because it's ungrateful, something that is good for me doesn't necessarily mean that it's good to someone else and vice versa, one thing i can tell you is that your prices are low. Don't sell hard work cheap, if you do, you and your work won't be respected.