While everything I've tried from 3D/HD has been exceptional and priced very reasonably I have to say the most impressive to me is 3D 50:1 Glass Cleaner. Perhaps it's becuause it's a product I use more often than Polish or Poxy etc or perhaps it's because it addresses the one area of detailing that I absolutely despise-- cleaning the windows especially the interior windows.
After applying the 50:1 Glass Cleaner the initial wipe creates a visible haze on the glass -- as the second wipe revoves the haze you can feel the change in slickness. Between the haze and the grabby feel being removed it's very easy to get a streak free clean window even in poor light. No worries about finding a smear the next time you drive the car.
And it's unbelievably in-expensive. I mix .5 oz of the cleaner, .5 oz IPA and 23 oz of distilled water so it works out to just about $.50 per 24 oz bottle. That's using the 16 oz bottle of 50:1 price-- would be even less expensive with that larger bottles.