I have used a bunch of different readers, and my current one connected to my MacPro is a Lexar pop-up that has UDMA SD/SDHC and CF slots and is USB2:
http://www.bhphotovideo.com/c/produ...W035_001_Professional_UDMA_Dual_Slot_USB.html
It is connected to a USB2 hub and at the end of the day was just as fast as this Lexar FW800 CF only reader:
http://www.bhphotovideo.com/c/product/492648-REG/Lexar_RW034_001_Professional_UDMA_FireWire_800.html
I also have a mini non-pop-up Sandisk SD/SDHC CF combo reader for my laptop that is just as fast as the pop-up Lexar. Looks like this one only SD and CF slots:
http://www.bhphotovideo.com/c/product/558993-REG/SanDisk_SDDRX3_CF_A31_Extreme_III_USB_2_0.html
Oh, and my USB2 hub on my MacPro is a combo 7-port USB2 hub and 23 in 1 card reader. It is a tad slower than the units above for my Extreme III cards, but not much. The best any of them do is about 2 gigs a minute, or 30GB/sec -- which I think is as fast as the Extreme III's will run anyway... I understand the Extreme IV's are faster.
Your hub could be the problem if it is a USB1 hub -- but regardless, this should be *really* easy to confirm, no? I mean time a transfer of the same amount of data via each connection and compare the result ---- presto
Finally, one thing that can really slow down transfers is if your target drive is an external connected to your system through the same USB hub as the reader -- they have to compete for bandwidth on the hub. Here it is always going to be fastest if your target drive is connected to the motherboard or a totally different path like a firewire port.
Cheers,