No, not on a GPU level. In some cases they overclock better. As a general rule there are two kinds of cards from other sellers: "reference" cards and custom cards. "Reference" cards are those which are the exact same design as the the stock card. The only difference is who is manufacturing the PCB the components are on. Within custom cards there are two types: fully-custom and "semi custom." Semi-custom usually means that it is the reference PCB layout with a new cooler on it which is usually more effective at dissipating heat or quieter, or both. "Fully Custom" usually means that the manufacturer has designed the PCB differently and it generally includes more robust power delivery circuitry and higher quality components but the GPU itself is the same. These nearly always have different coolers on them.
Don't bother paying the extra money for a fully custom card unless you overclock, as that is its primary value. I would suggest getting the custom cooler in most cases, though the 780 ti and 780 have a very good stock cooler which you would most likely be quite happy with as well.