UPDATE: I discovered that there was a f/w update available for my printer. After installing it, I decided to go back and try some of the apps that had failed earlier. Since my Dell V715w printer is made by Lexmark and essentially the same as their model Pro715, I decided to try the Lexmark app first. Nope - still nogo. It could not even find the printer on the network or acknowledge its existence... even after manually entering the printer's ip address. Bear in mind that the Pro715 is one of the printers listed as "supported." I guess this is an example of why it is so lowly rated on the Market.
Next up, I tried my first choice, PrinterShare. To my pleasant surprise, it now works perfectly (and better than EasyPrint). This does everything I need for now, so I'm not going to test further.
It still kind of annoys me that Samsung made a big marketing splash announcing that its last update to the GTab 10.1 added native printing, but they failed to mention that it is only for Samsung printers. Arbitrary bs like this will backfire on them. They may think it will cause people to buy their printers, but it just makes me want to never buy another Samsung product at all (and this from a household with 2 Samsung phones, 2 Samsung tablets, and a Samsung dishwasher).