Are these usb flash drives any good?  

Megahertz said:

Does your computer has USB 3.x ?
Read speed is up to 130 MB/s but write speed is unknown and can be much, much slower.

My suggestion is to buy a 2.5" SSD and a good USB caddy. Faster and less expensive.
A USB caddy with NVMe drive inside is the fastest you can get (up to 1200 MB/s on a USB 3.2 port).
Unitek M.2 NVMe SSD Enclosure, Newegg.com
Crucial P2 500GB 3D NAND NVMe PCIe M.2 SSD - Newegg.com

Exactly as you suggested.
My external Transcend SSD is much much faster than any usb flash drive.
But I have the mentioned SanDisk Wireless Stick USB 16GB which is really fast in read and write too when it is connected to a USB 3.0 port. Of course, not so fast than my external ssd but much better option is this usb drive then the Kingston DT100G3/256GB.

Our PC's are all compatible with USB 3.x

A hour before this post I received the
Kingston DT100G3/256GB.
I tested it in several situation, as I expected, it is a piece of S..T!!!
Avoid to buy this crap.

My old SanDisk Wireless Stick USB 16GB is 5x faster in any data direction then this crap.
I will return this S..T.

To transfer ~650Mb from my PC it takes around 8min...
On my external ssd it takes under 50sec
On my SanDisk Wireless Stick USB 16GB it takes ~2min.
I tested the same data, same amount.

I have several Kingston drives of these types, tested in USB 3.0 port, obviously slight cosmetic differences with model number.
1) DT100G3 32 GB.
2) DT106 128 GB.

1) average tested write speed is around 25 MBytes/s with 1 GB files.
2) average tested write speed is around 32 MBytes/s with 1 GB files.

Read speeds approx double that.

They are standard cheap USB key drives nothing special, you pay a lot more for higher speed ones.

Do the same with mixed sizes of files and copy stuff with Windows File Explorer will result in much slower/varying speeds.

Going by Kingston's data sheet for DTKN/256 they should be a bit faster, but there are variation in all mine by a factor of 2-3x with those 1 GB file sizes.

Have a look at Nir Sofer's USB speeds reported by users.

I have several Kingston DT3 and DT4 USB 3.0 sticks and think they are great... but none are as fast as my 256GB M.2 drive mounted in a USB adapter.

Hope this helps...

RickC said:

I have several Kingston DT3 and DT4 USB 3.0 sticks and think they are great... but none are as fast as my 256GB M.2 NVMe drive mounted in a USB adapter.

It seems to be a SATA M.2, not a NVMe.

Anibor said:

It seems to be a SATA M.2, not a NVMe.

Oops, you're right. I've corrected my post.