I was referred to Smartscript Solutions by a friend who purchased their Domain Trader script about a year ago. I was a bit hesitant to purchase at first, given the high price tag of the script, but I finally bit the bullet and bought it 2 weeks ago. I bought Domain Trader to sell my portfolio of over 2000 aged domains. The script was definitely not easy to install, but I managed to do it after making a few changes to the server's settings. I do want to point out that the company offers installation for an additional fee of $100, but I chose to do it myself. Once installed, the script was easy to set up and load my domain portfolio into. The domain sales and auction functionality is very polished, and with the latest responsive theme that they released (which is what I am using), I feel that my site will be future proof. I can recommend Domain Trader if you are looking for a script to sell your domains. I am not using the parking functionality yet, but I plan to do that in the near future.