In fact I'm going to launch into a Linux/USB related rant. USB, particularly USB Storage, support in Linux has always been extremely crap. I've never really found it to be reliable. It might not be Linux's "fault". It might be crappy cheap Taiwanese hardware that is the problem but Windows seems to handle this cheap hardware much better than Linux does.
I've had the opposite experience. My first use of USB mass storage and linux was with RH 7.3 and an external USB cdwriter which worked cleanly on a brand new install of RH 7.3. Zero problems.
Currently I'm having the vast majority of my problems with my USB2 external HDD. It is based on a Prolific Technology USB ATAPI-6 Bridge
I currently own a New Motion 3.5" IDE-> USB2/firewire enclosure, and have had no problems with it under linux. I used to own an ICE enclosure of similar nature, but its power supply died, so I had it replaced. When the replacement died in the same fashion, I asked for a refund and changed brands. I also used firewire mass storage under linux, and found it to be very good with both devices I used. I didn't do a decent throughput comparison between USB2 and Firewire, but I suspect in both cases the single disk was the bottleneck. The only problems I've ever had with USB mass storage was when I was running a 2.6 -mm branch kernel, which isn't exactly surprising. One problem with removeable drives under linux is that mounting them in specific places becomes slightly tricky if you have more than one device. Under windows you just get 'next drive letter', which is normally ok. You need fstab entries to have things automounted under linux however, and if your insertion order changes, your device order changes, and so you mount things in the wrong place. There's a couple of fixes for this: I make use of udev at home, and dynamically create device nodes named specifically for the device I'm plugging in. Eg, my 512 MB memory stick gets assigned /dev/memorystick, no matter when I plug it in. Likewise, my external harddisk gets assigned /dev/external Another solution is the gnome-volume-manager, if you use a recent gnome. Not being at my home computer right now I'm a bit hazy on the specifics of this, but I beleive it rewrites part of fstab for you (yes, a potentially dangerous thing, but "safe enough" on a single user system). It'll then auto-mount devices for you.
On the whole, fucking crap. Perhaps one day we'll have decent USB storage support in Linux. Until that day I'll just continue to bitch as I don't have the knowledge to fix it myself. *sigh*
It's possible it's some combination of your controller and the device itself. It's also possible that the Fedora Core kernels are tracking some changes from the -mm series, which has caused some instability in some specific areas.