every advertised usb speed i've seen in my life has been grossly exaggerated.
read speeds are not an issue to me, I've never really had any issues with read speeds with usb drives in my life. but maybe i'm not remembering anything correctly.
write speeds are where it's at for me. for usb 2 drives, the write speeds are never more than, say, 20 MB/s. Maybe sometimes it will burst high, but usually i think they are in the 10-20 range.
for usb 3, i have hit the 80-100 MB/s range, but only with an SSD drive inside an enclosure. And even that wasn't terribly consistent. Depending on the computer, or the situation, I've even seen that commonly go to the 30-50 range.
for thumbdrives, I've never had great speeds, regardless of the advertised speed or whatever. Thumbdrives are just going to be slow. And the usb 3 offerings for thumbdrives suck.
I don't even know if it's the thumbdrive problem. There is something wrong with USB 3 in general, it's not very reliable. I've tried transferring a large about of data to an external drive connected to USB 3...wether it was an SSD, or flash, or mechanical drive...and things usually go wrong. Often times, the drive will disconnect in the middle of the transfer. SOme of my research has shown me this is common, and not resolved, and people aren't very sure what the issue is. There is something wrong with USB 3. Drives have become corrupted on more than one occasion.
There is one great thing that has helped me...I bought an extra external power USB cable to use with my external drives, and that seems to be a great help (I got it from addonics). So I plug the external drive in the usb 3 slot, and i plug an additional power cable to the enclosure. This makes the transfers much smoother. SO USB 3 may have a power supply problem. Still, I feel something is wrong with it fundamentally.
i recently was able to get about 100 MB/s, consistent and reliable, with the mentioned power cable with a inatek usb3 enclosure on my tablet and the extra power cable (mechanical 2.5 drive inside). Without it, the tablet couldn't even read the drive. it would literally connect and disconnect constantly. and in the past, without the extra power, the drives have become corrupted and needed to be reformatted. be careful with USB.
esata has been good to me. No problems usually. But my esata drives usually have external power connected anyway. It might just be a power issue. Which may be why all the thumbdrives suck, is because they don't have external power.
I personally have always had problems with usb as far as speed and reliability. For convenience, it's great, but for transfers, not so much.
and what frustrates me the most is that there just doesn't seem to be much discussion about these real issues with USB. Again, one time I found this one guy who had done quite a bit of investigation and had proven that this is not a driver problem, or an enclosure problem, or a manufacturer problem...but really a USB problem.
If you were to ask me, I would like a little more attention given to other platforms like esata or thunderbolt. but there is politics here. I think the important people know about this power problem, but there isn't enough demand to fix anything at this point.
Case in point, a couple of years ago, I got a vaio laptop that had a special thunderbolt implementation. Did it have an actual thunderbolt plug? Nope. guess what it was? it was a funky USB3+power cable. And it kind of worked pretty well compared to other USB 3 implementations I've seen. So that means sony is aware that USB3 needs additional power to do anything that the advertised specs say. yet hardly any USB3 implementation have the extra power (talking about thumbdrives and stuff, for obvious reasons). see below for the plug I'm talking about:
so my point is, no matter what anyone says, I would never expect much more than 30MB/s write speeds with any kind of USB device that doesn't have extra power.
Also, the only time I've seen awesome write speeds (as in, over 80 MB/s consistently) is with good RAID setups. I've gotten 50-80 with software raid, which is ok. I've gotten almost 200 MB/s with SSD raid (two drives). I've seen videos of people getting crazy high, like 400 MB/s, with some good Raid setups.
I just ultimately feel the consumer market for thumbdrives is not getting the attention needed to get the higher speeds. I think the technology is there and available.