Why is it unique? because of the case, it's an old discontinued case from bitfenix. Tried to add it but it is not included on PCpartpicker's list. It's a Bitfenix Colossus M micro-atx case (USD 65). A small case with an upside down motherboard configuration and a PSU at the front. A real challenging case to build on and placing the case fans was quite tricky.
Also the PSU was not in the list, it's a Deepcool DA600 bronze rated (USD 58). That is why my list costs less because of these two parts that was not included.
So this build totals USD 773.93.