The USBConnect Quicksilver was introduced by AT&T and Option in October 2008 not only as one of the world's smallest HSPA USB devices but also as an intelligently designed accessory that "projects a confident and refined image" (via press release). Having just reached the end of my 30-day trial period with the Quicksilver, generously provided to me by Option, I can say that while I agree with the first half of that statement (the modem is small), I do have some issues with the second.
Here are the specifications from AT&T:
Like the USBConnect Mercury, the Quicksilver features plug-and-play software installation. Setup, then, is very simple: just plug the modem into a USB port and follow the on-screen prompts to get the required drivers and AT&T Communication Manager (ACM) software installed on your computer. Note: If you already have another copy of ACM, as I did, uninstall it before plugging in the Quicksilver.
Connection and download/upload speeds are the same as on the Mercury (up to 1.7Mbps down and 1.2Mbps up), so the only feature worth discussing here is the design.
You can see for yourself that the Quicksilver really isn't much to look at. It's incredibly understated with the most interesting visual elements being the swiveling cover and a circular indent that looks like a place to rest your thumb but is actually an LED status indicator.
The multicolored lights are quite nice, but the swiveling cap, which "clicks" into four different positions but will stay in any angle with no problem, is rather cumbersome.
The benefit of the design is that it eliminates the possibility of ever losing a standard removable cap; however, it actually takes longer to get the USB connector exposed because of the slow/tight swivel (i.e., you can't just casually "flick" it into position; it requires several deliberate motions). A retractable connector would've been better.
Another "intelligent" design choice that backfires is the offset USB connector. Though it was intentionally off-centered so it wouldn't block other USB ports on your computer, it actually does exactly that.
Take a look at these shots of the Quicksilver and Mercury plugged into the same ports on my Vaio TZ (same thing happens on the Samsung NC10, Raon Digital Everun Note, and an old iBook):
Sure, I could just move the Quicksilver to the left port, but I can do that with the Me rcury too. Rather than not blocking other USB ports, all the Quicksilver's offset connector does is force me to plug it into the port on the left.
Oh, and did I mention that the Mercury also has a microSD card reader? In other words, if you ever have to choose between the Mercury and the Quicksilver, get the Mercury.