I don't have vast experience with them, but my opinion is sort of in the middle, in that they are good value for the money and with hard-to-find 27" wheels (with decent Chinese Weinmann hoops) going for as little as £25, they can certainly breath some new life into an old classic. I find that the first part to go cosmetically on many bikes is/was the spokes. And if you spend two hours cleaning them up, they rust again very quickly. Shimano (and let's be honest, they make some low-low end stuff, too) hubs seem to be about £20 more at least when built into a wheel. So, overall, I think it's good to have a choice - cheap Quandos to pretty something up, then better wheels if it becomes a regular ride. I would expect the fronts to last longer than the rears, of course.