I am glad to be able to answer your questions. I don't think I ever found the MG5320 for $50-60. The reason ours is marked up is because we offer a one year warranty within the Continental US. In addition to the warranty we offer supplies with ours as well as a free trial to iDesigns and free use of iPrint. To answer your specific questions:
1. The printhead is not removable. I am not sure why he would say that it is when it is clearly not removable. This is important because it makes it very hard to clean it should you have a deep clog.
2. Icing sheets have to be pulled from the bottom: On the 5320 there is a rear tray. This allows almost a straight path for the paper to follow through the printer. This is ideal for icing sheets. The bottom trays require you to put one icing sheet in at a time. Icing Sheets should never be put in more than one at a time as they are more prone to jamming printers when you stack them. So every time you go to print you will have to open the tray and put the icing sheet in. If you plan on printing pre cut circles, you will find inconsistencies when the icing sheet is pulled through the printer causing you more waste as you will find it nearly impossible to line them up to accurately print. If you plan to print 8.5x14, you will find that the tray does not properly hold it and that the tray is too short so the icing sheet sticks out of the closed bottom tray. It is a bad design and one that is prone to complications.
3. Sponged cartridges: Since our company switched to cartridges with no inner sponges we have found more successes then ever before. We are currently at the fewest problems with cartridges/printheads/refilling then ever in our history with the current cartridge design that has no inner sponge. Are they perfect, no, but they the problems with them are so few that I will do my best to stay clear of sponged cartridges if I can as it is my job to sell the best possible product that I can.
The 5420 prints just as good as the 5320, but the frustration level based on the items listed above makes it a high risk. If paying a bit more gives you a more reliable printer, to me it would be worth it. If you get a bad clog, you may find yourself buying another printer and then another.
I will tell you that in our testing with our cartridges and our inks we have not been able to clog it as of yet. We are trying to get it to clog so we can test some theories in getting it to clear a clog. But not all inks are the same. Some companies that may sell the product may not have the same quality inks and may not have the same standards that we do. Depending on where you find cartridges for this printer, you may not find the same successes that we have had with it. But If our customers buy this products, they need to be able to fix problems that may occur effectively. So we are moving closer.
In summary, we feel at this point, until we are finished trying to resolve the issues found with this printer, you will end up spending more money and time fighting with this printer than the investment you would make in purchasing a higher priced model. I can put these cartridges out on the market now and earn all kinds of money off of people who are desperate, but it would not be the ethical thing to do. I know from the experience in working with these newer models that they are prone to more problems then not and if I sell the cartridges that we have in stock and do indeed work, I would be doing a disservice to you.
I will tell you that we are trying to work on the solution and we are hoping to have a solution for you soon, but I will not sell printers or cartridges that will cause my customer problems. I believe in taking care of my customers and being honest with them and not steering them in a direction that I know to be wrong. I am sorry that this is not something you really want to hear, but again, I believe in selling only good quality products that you will be as happy as possible with. Perhaps you may want to out source until the problems are resolved. Spending the money on the printer and the cartridges and paper and having difficulties can be more of a waste of money than not.
Please let me know if you have any other questions and I will be glad to assist you.