I bought 4 watches from Bidz. Two of them are lovely, one is OK, and one is horrible (looked much worse than in the photo). All of them came boxed with the manufacturers' warranty etc, and were nicely presented.
In retrospect, I probably wouldn't buy these watches again - not because they were defective (they're perfectly fine) and not because they weren't reasonably priced. Mainly because they were the first things I ever bought to sell (haven't put them up in auction yet, but will after easter), and I didn't really grasp at that stage just how competitive a marketplace ebay is. Just because you get something for a fraction of the price doesn't mean that somebody else is necessarily going to want to bid on that item and buy it from you. So now, what with the high cost overseas postage, I now know I'll be lucky to break even and get my money back, let alone make a profit.
I suppose if that's the extent of my newbie mistakes, then I haven't much to complain about....
Mind you - I don't know about rings. I haven't bought any of them from Bidz. However, from what I've seen in TV news reports, etc, this sort of misrepresentation of the quality of diamonds isn't limited to Bidz.
Claws on diamond rings can be tricky. They need to be serviced every 12 months or so and are pretty expensive to get serviced (so my mother tells me, which is why she doesn't wear hers much now). Claws can get caught on things and stones can fall out. I had to replace my blue topaz in one of my rings about 2 years after I bought it - looked down and it was gone. But they shouldn't be falling out if the thing is brand new before it's worn!!!!