I bought a BL-5J from ebay from hong kong. Cost me 1 cent for the battery and 4.59$ shipping. I hasn't arrived yet, but generally about these batteries (I did a lot of reading on the subject before buying):

- Very low risk of "boom" and "exploshuns" and whatever nonsense. This can happen with most batteries, but even after market OEM suppliers are not doing this intentionally. They do have QA, even if the batteries are of inferiour quality.
- Some (but not all) of the cheap aftermarket batteries are in fact the same batteries as sold by the original seller. Same OEM supplier, same internals, different packaging.
- Many of the aftermarket batteries are of weak quality. Expect shorter-then-advertised running time - 60% should not come as a surprise. On the other hand, they're easily only 20% of the price of a genune battery

Bottomline being: Don't be paranoid and don't expect too much of them. My recommendation is:
- Buy those cheap aftermarket batteries as a backup. When your main battery dies, it's nice to have another one, even if it lasts only a couple of hours. It was dead cheap and takes no space in your bag.
- Don't buy those cheap batteries as a replacement for the main one. If after a couple of years your main battery is done for, get a genuine replacement. Of course you could try an aftermarket one, but it will possibly disappoint you.


BTW (!): At the moment, hong kong post has a backlog of two weeks because of missing shipping lines. Many sellers from hong kong have delayed shipping (I ordered my battery 2 weeks ago, I expect it to arrive in another week or two). Here's the official statement: http://www.hongkongpost.com/eng/misc...204a/index.htm