Excerpt: I was deciding between this and the sans disk card that writes 280 MB. Im glad I went with panasonics proprietary card. its almost half the price and It works great for recording 4k or 96fps and gives you about 42 mins recording time in 4k. Great card much better price I've bought a couple for my GH4.
Excerpt: Use primarily for 4K video in the GH4. So far no dropouts or bad records. Read speeds when transferring to computer are near the stated 90MB/s. Bit expensive for slower speeds than some of SanDisk's products.
Excerpt: I received this when I purchased the Panasonic Lumix DMC-GH4. They emphasized the U3 being necessary to record in 4K. The card works but I will compare it to the SanDisk Extreme Pro with 95 MBS Read and 90 MBS Write speeds. Even though the SanDisk is not U3 the read write speeds I tested were much higher than the panasonic. Using the "Burst" feature when taking pictures in RAW format both memory cards caused the camera to stop taking pictures..