Pretty decent deal for 400GB, UHS-I is sufficient for all phones, and almost all DSLR/mirrorless on the market unless you really need UHS-II.
Bought one myself for Canon EOS R and got delivered in 2 days, actual transfer speed floats from 90MB-92MB on my machine and card reader, average over a transfer of 6TB of data across photos and videos.
Agree with you on the adapter and limiting of SD card capacity in fear of corruption etc, and I've heard and read about many horror stories involving both, however from a personal experience of using CF/SD/MicroSD for the past decade I've never had a card fail on me, knock on wood. Have been using the 400GB card for the past week and it's been more than I was expecting, but of course, like I said, all of your points are valid concerns.
For EOS R, I’d recommend the Sandisk Extreme Pro if you want to make the most of it. This ultra is two levels down In term of write speed which is important in a fast high resolution, high bit rate full frame camera (there is a Sandisk Extreme in between).
At the framerate of the EOS R for photos, and the highest recording capacity for videos, there's zero benefit to get a higher speed card as the camera simply does not take advantage of it. But like I said UHS-II would obviously be better for the transfer speed to PC, which, one could argue the time saved is the time saved and could be worth more than financial justification.
Delivered in 2 days? Where was it sent from?
I've already thrown away the packaging so I'm not sure sorry, was pleasantly surprised. Thought I'd mention it as I've seen plenty of deals from them in the past but never ordered anything from them myself, just sharing personal experience.
are these cards genuine? I've seen some reviews on amazon of buyers receiving fake sandisk cards ://
Using this 400GB model in my PS Vita, excellent portable emulator device. Though I got it for less than this a few weeks back.
I would wait for the A2 version of cards, having said that they need to be compatible with the device. See below:
A2 performance is 4000 read IOPS, 2000 write IOPS.
A1 performance is 1500 read IOPS, 500 write IOPS.
SanDisk A2 MicroSD Cards
SanDisk has introduced the MicroSD A2 cards to the market. The A2 cards have extreme speeds for fast transfer, app performance and 4K UHD video recording. Performance of the A2 cards read speed is up to 170 MB/s and write speed up to 90 MB/s.
SanDisk's latest proprietary technology has enabled performance beyond UHS-I 104 MB/s limitations.
The A2 cards are compatible with our SanDisk Mobilemate USB 3.0 Micro SD card reader (SDDR-B531) to achieve host device speeds up to 170 MB/s. https://www.sandisk.com/home/memory-cards/memory-card-reader…
IOPS is a performance measurement used to characterize computer storage and devices.
Please note: In order to achieve the best performance you'll need an A2 compatible host device. Results may vary based on host device, app type and other factors.
source: https://kb.sandisk.com/app/answers/detail/a_id/21206/
If you're using it in a camera especially one that takes full size SD cards, I'd recommend you stick with normal full size SD cards.
The reasoning is the adapter is an additional point of failure, and unless your camera has dual slots and you are recording to both why take the risk when you don't need to.
Also you're talking read speeds of 90-92MB which is about not too shappy, but the write speeds for this card is bang on average. Perfectly fine for Nintendo Switch's or storing media on your phone/laptop/tablet. But if you use it in a modern DSLR or video camera there is a good chance you will bottleneck, especially in burst shooting or video recording.
It's also good practice in photography to use smaller cards than this, probably 128GB max (unless you predominantly shoot 4k video) and just switch cards. That way in case a card fails you don't lose everything. Large cards like this just encourages you to not format your cards regularly. Also using multiple small cards mean you can offload images whilst shooting on another card.
Some of this stuff mostly likely won't apply unless you are doing serious/pro work but just some tips.