@fredx181 :-
Hi, Fred.
Mm......couldn't really say. I only tend to upload single items at a time (I don't think I've EVER uploaded anything containing lots of small files). Which, being the case, means I can neither confirm NOR deny.
I wouldn't describe their upload/download speeds as blazing fast, but they're hardly slow, either. It's been quite a number of years since King's Lynn's telecom infrastructure was upgraded. I'm certain we're nowhere NEAR the top tiers of fibre speeds/bandwidth, that's for sure.....
Geographical location will doubtless play a large part. Somebody in one location - accessing my stuff - might get a fast download, while somebody else in a different part of the world might get a very slow download and have a bad experience. That stuff is completely out of our hands, of course!
Curiously, for ME, the fastest one I regularly use is my MediaFire a/c.......and I believe THEIR server farms are ALL Stateside, across t'other side of "the Pond" from us. You'd never know it from the speeds, though.
Could be to do with whatever verification software they're using. You ARE aware that, regardless of provider, they all insist on verifying/running checksums on every single item you upload/download.......irrespective of size? 
Mike. 
).
) to fix it, just wasn't in your COMPLETE list.