USB flash drives usually use the worst flash memory available. There are good ones but they are hard to find and expensive. Going for a NVMe SSD in an USB-C enclosure gets you way more reliably better speeds and durability.

A USB stick will be fine for ventoy unless you are using persistence and writing lots of data to it.

An NVMe drive in an enclosure is better if you don't mind the larger size and higher cost. A good NVMe drive will contain higher quality flash memory and have better wear leveling than a USB stick. There are USB 4 and thunderbolt enclosures available that can transfer over 3 GB/s.

flash vs ssd is night and day difference for write speeds. if you write that frequently to your ventoy and write speed matters to you, you want ssd.

either make it (assemble) yourself or buy one. i have a number of clients using samsung t7 external usb ssd. they seem pretty fast to me.

i don't use ventoy or ventoy-like devices that often, i just use flash.. even some usb 2.0 ones. yea, they take longer to boot up and longer (much longer) to write to, but i don't add or replace iso on them very often.

Definitely go with an external nvme enclosure

If you use a usb 3.2 gen 2 port, your max speed will be 1250 MB/s, pretty much every nvme ssd will be able to max that. Fast USB sticks will undoubtedly be very close, but might not have the same sustained write speeds compared to an SSD (With Dram cache).

If you're just going to use it for recovery ISOs or installations it's probably not going to matter much, I regularly use USB 2.0 usb sticks for that purpose just fine.

It's up to you though, I had an nvme ssd laying around and bought an enclosure for it, I get about 1000 MB/s read and write with it.

So if you have an ssd laying around I think that would be a good option, but a usb stick will be fine as well and would be a little bit more compact, if that matters to you

Nvme would be much faster, I personally use the one from ugreen which is ~30€ plus a nvme with 2-3gb read/write speed for around 100€. You can find 1tb for 100€. I don't know any good USB sticks that can do that much

The flash drive will go full speed for a minute or a bit more and fall down to slow speeds while an NVME with a good enclosure that has a properly fitted heatsink can maintain much higher speeds indefinitely We're talking 200 MB/s at most for a minute then about 50mb/s VS 800 MB/s the whole time

I have done some basic testing, and the speed of the USB stick you use does make a noticeable difference on the boot time of whatever you install on it.

If I recall correctly, A low speed USB 2.0 stick took around 30-60 seconds to load (either time to login screen or time to reach a blinking cursor for something like an arch install disk). If this is something for occasional use, even this works perfectly fine.

Slightly faster USB 3 sticks in the 100MB/s range can be had for only around $5-15 USD and work significantly better, maybe 7-15 seconds. These usually have assymetric read/write speeds, such as 100MB/s read and 20MB/s write, but for a boot disk the read speed is the primary factor.

Some high end flash drives can reach 500-1000MB/s and would load in only a few seconds. A high speed 256GB stick might cost $25-50, and a 1TB stick maybe $75-150.

An NVMe enclosure might cost $20-30 for a decent quality 1GB/s USB 3 enclosure, or $80-100 for a thunderbolt enclosure in the 3GB/s range so long as your hardware supports it, plus another $50-100 for a 1TB NVMe drive itself. This would of course be the fastest, but it is also bulkier than a simple flash drive, and I think you are at the point of diminishing returns in terms of performance to cost.

I would say up to you on what you are willing to spend, how often you realistically intend to use it, and how much you care about the extra couple seconds. For me, I don't use boot disks all that often, so an ordinary 100MB/s USB 3 stick is fine for my needs even if I have faster options available.

I have a 32gb USB flash drive I got from Protectli with some other purchases I mad (it was cheap and is tiny and metal) I was surprised how fast it was, so I am using it for my ventoy boot disk and have 15+ isos on it.

I actually just used it last night and copied windows10, debian 12.5 and Linux mint isos

They all copied pretty quickly!