Woah, where did you read bout that? Was transferring the files earlier, seems pretty ok....
"*Edited my review after 1 full month of use. Down from 5-stars to 3-stars. The reason being is that my battery life has drastically reduced. Typically on my MBA 2013, I was getting around 8-11 hours while traveling. Now, I'm only maxing around 3.5 hours at full charge. The battery drainage compared to what this card offers is just not worth it. So as a secondary card, I really like the speeds as I reported. However, to always have it mounted as an external, completely not worth it.
I purchased the JetDrive Lite 130 128GB here on Amazon for my 2013 13" MacBookAir.
First, it is formatted in ExFAT and I had to research to understand why. It seems it does have a speed edge over HFS+ so I'll be keeping it as is (plus the I don't have a PC if I want to reformat back to ExFAT). I have no problems with Read/Write, works right out of the box so not sure what the issue is of others reporting that it's write only. I renamed the drive and have copied files back and forth.
I ran BlackMagic Speed Test and I'm getting avg 52MB/s Write and 85MB/s Read as you can see the photo I uploaded. I ran this with a 5GB file.
Overall, I'm quite happy with it. My only complaint is how I might use this. I was so excited to get it I didn't really think through what I would store on here. Because of how almost flush it fits, it's not good for sharing files as it'll be incompatible to place into other SD supported devices. It really is just a secondary hard drive. And since I primarily use my laptop at home connected to a Thunderbolt display with a Thunderbolt drive, I don't need it as a scratch drive (my Thunderbolt drive gets 240MB/s Write and 320MB/s Read speeds so no need to change). I might just store it with movies and such that I might need while traveling.
Anyway, if my only problem is finding what to put on it, then I'll be fine. I was thinking of using it as a Time Machine backup but it's too small compared to my internal HD size. But then again, to always have it mounted might be a good thing."
http://www.amazon.com/Transcend-JetDrive-Storage-Expansion-TS128GJDL130/product-reviews/B00K73NT0S