I agree with everything said so far, I've really enjoyed shopping with both companies since I got into collecting pearls a few months ago.
I've purchased the most with Wen. I love my tahitian multicolor strand, and I'm pleased with the loose pearls and half-strand of circled tahitians I've bought for a harvest strand project. She tends to list out in her description either 2A or 3A for quality. The 3A, either in loose or full strands, have much better color and luster. Freshwater strands from her are a little more hit or miss, but I've really only bought inexpensive keshi or small rice pearls so far. She replies very quickly to questions, and will send additional pictures of strands in different light to help you make a decision. Even when her pictures have made me not want to purchase, she was still gracious for my inquiry. I even bought a baroque tahitian pearl that STUNK, I mean real bad folks.... We're talking a barn full of cows that ate brussels sprouts bad.
After a few weeks I contacted her, and she had me pick out another pearl to replace it. I thought that was cool she'd ship a $8 pearl to me just to make it right.
For Kongs Pearl, I've only purchased one ripple freshwater strand and I'm very happy with it. They tend to take pictures of their pearls in a very artificial, light-box setting, so you're getting the best case scenario when you web shop. The strand was a little subdued when I received it, but once I took it in different rooms and rearranged the pearl order, they came to life. I would 110% ask for additional pictures from Kongs before buying any strand (which I didn't do....) but I think what they are putting online is accurate if that makes sense.
Maybe I'm just a hater, but I think for more expensive strands, Wen has better tahitians and Kongs has better Edison/ripple pearls? Thoughts anyone? I also agree that the big online companies, as well as the ETSY vendors on this forum are going to have top-of-the-line quality and are less of a risk as far as what you are getting.