I've premium-listed what I have in GoDaddy but don't have much reason to move what I don't have there to them to premium list those domains. It's not just the 30% commission, but keep in mind they are primarily marketing domains for "under $1 per month" per their commercials. GoDaddy may get a lot of eyeballs, but a lot of those eyeballs are useless from a retail sales standpoint. Maybe when they start educating their customers on the importance of a high quality domain vs whatever they can find that's available, they can convince more of them to get premium domains showing up on their search, but until then, the domain has to be a "must have" and/or everything else they looked at has to be taken in order for a buyer there to be inclined to pull the trigger on a premium listing. It's obviously not a priority for GoDaddy - in fact the person has to make an extra click after their search to even get to the premium listings now, and then scroll down the list to even see them all.
GoDaddy is and has been actually one of the biggest deterrents to secondary market sales even now with their premium listing capabilities - they have by far the biggest reach of any company in this industry, and their focus is, was, and probably always will be to engineer customers that find domains that are available and register them for $7+/yr. That's been their bread and butter, that's what got them the market share they have, so they have no reason whatsoever to get people to realize if they have more money to spend that they can secure a better name for their business and increase their chances of success online. They have always played the "cheap" route and it's worked for them in getting "cheap" customers including us domainers. Compare their commercials with pretty much any commercial during golf tournaments for example (where the target market is businesspeople and investors, the kinds of people we would probably be most likely to make end-user sales to) and you can see that GoDaddy's market is simply not the same and not even close. That's part of why this industry is still not truly mainstream - the pioneering force in our industry is all about using sex to sell cheap products to beer guzzlers during the Super Bowl.
I'm not even sure the average non-domainer GoDaddy customer would even understand that the prices on those premium listings is NOT per year...they are after all paying monthly or annually for the products/services they buy there - they might not realize that the premium listing prices are one-time cost + the ongoing registration renewal fees instead of an annual cost.
So I'm not surprised I haven't sold anything there yet and wouldn't be surprised if I don't make a sale there all year - and in the meantime will probably still be yielding sales from Sedo, Afternic, forums, past buyers etc. as normal. I'm sure it may work well for some people but I just don't see it being truly AMAZING for anyone that's currently using the other means of reaching buyers that are out there.