The only brand I know of that is fairly good is Deteknix/Quest. Their XPointer works very well. It detects an inch or more farther than Garretts' (I have both) but it also burns through batteries much quicker. I tried one of their Quest detectors too. It worked well but still had some iffy things that reminded me of the Teknetics T2 like the audio, tone breaks for iron, detecting characteristics and even some of the on screen labeling which is probably why they are being sued a second time by First Texas.
I totally agree with most of the other posters. I would rather have a used product from the US, Australia/Malaysia, France, Turkey, England or any manufacturer that is not knowingly infringing on standard patent laws. I know that many parts for detectors are made in China, Taiwan, South Korea, Vietnam, Indonesia and Malaysia which is great for them and keeps our prices down, hopefully (or more likely increases some companies profits.)
The GP pinpointer stuff I tried really sucked. No comparison to the real thing=Garrett and Whites no matter how low their price is.
If you are on a tight budget buy used until you can find enough to buy new.
Jeff