Is the MPC suggested 615 better or worse than the 655? What's the limitations, and how do we deal with them now that it's purchased based on MPC putting it in print?
The 615 is a less expensive model with less features then the 655. MPC based their article on how their device performed in the Lab, there is no way to simulate every possible environment that the device will be operated in. They also can't predict product failure. Three things cause wireless router issues, Environment, User Error, and Device Defect. None of which can be blamed on MPC. That's why I suggested that the OP research to see if his problem is common amongst other users with this model, this could indicate a possible device defect or issue.
I have suggested the 655 to countless people (including you) both on the internet and in person. I don't own one, and I haven't even touched one in RL. I suggest it based on features, reviews I have read, Customer testimonials, and the firmware emulator on Dlink's website. Should I be held liable because someone bought one on my suggestion and it ended up not working for them? I think not.