A few years ago I bought from dealextreme.com brandless heasphones described as "BH-503 Designer's Bluetooth Stereo Handsfree Headset" (used to be SKU 30407, now removed from the site). What I received was a Nokia branded product that had very good build quality. I believe the packaging also looked like genuine Nokia. All in all, one could easily mistake this product for a genuine Nokia. This pair of headphones served me well, had very good battery life and was comfortable and easy to use. The problem is that the earpads eventually worn out and there seemd to be no way to buy replacement pads. I decided to buy another pair. I searched ebay for BH-503 and ordered what looked similar to my pair.
The headphones I received was anything but the same. The main difference is that the band of new pair is significantly smaller, so much that I can't use it. It may be suitable for a child or for someone with a really small head. Other differences - the packaging is cheap and lacks instructions. My phone BT shows the new pair as "BH-503" (the old pair identified as "Nokia BH-503"). The LED flashes in disco-like colors while waiting to be paired. The old headphones flashed in blue. Also, the blue LED is not as bright as the old one, which is actually a positive as the old pair LED was blinding bright. Note that I'm not using these headphone for music but rather for listening to voice only (mostly podcasts and narrated articles in Umano). Both sound fine for this purpose, but the old pair sounds a bit better (less hollow).
Here are some pictures of both:
Old pair is on the left. You can see the difference is size.
Old pair - worn out pad but rather tight production tolerances.
New pair - all wonky. Note the USB connector as opposed to the round power connector (used by Nokia on many phones)
Old pair - Nokia branded (though probably fake). Light color marking on buttons.
New pair - unbranded "Bluetooth" label. Buttons are black. Red volume buttons feel very mushy compared to the old pair.
My plan is to detach the earpads from the new pair and use it with the old one, then trash the new pair. If that doesn't work then I'll just look for a different kind of headphones. Hopefully the experience will be as positive as what I had with the old "Nokia".