I changed my workstation just recently from an old, heavy Lenovo with 2 hours of battery life to a new Acer W700 hybrid that is half the weight and has roughly 7 hours of battery life.
Chief among the differences include only a grand total of 1 USB 3.0 port on my W700 as well as 64GB SSD instead of my old 128GB SSD + 500GB HDD combination. Anyway, I was long overdue for an upgrade to USB 3 so off I went purchasing a new usb hub and HDD docking station. I went for an unpowered USB 3 hub and a docking station capable of fitting both 2.5" and 3.5" HDDs for more flexibility. I was reluctant to get a powered hub as I already had so many powered devices. 1 for laptop, 1 for monitor, 1 for docking station.
Anyway, I only found one unpowered usb 3 hub. Many forums claim that with the increased power consumption of USB 3, unpowered hubs were not possible. But I wasn't going to attach multiple power hungry USB 3 devices. My docking station was self powered, and I would be attaching a phone charger, wireless adapter and mouse so I figured that it should work fine. I bit the bullet and took the plunge.
The items have just arrived and after hooking up, I am getting speeds of up to 100MB/s read, which I believe is the bottleneck for the HDD. Anyway, its 3-4x faster and I am definitely a satisfied customer. Due to my small SSD, I am now storing all my backups, data and VMs on a separate HDD which explains why I need the additional speed. Running VMs over a USB 2 connection was really testing my patience.
Testing both direct connection as well as through the unpowered hub, the speed difference was negligible. Granted it was not a stress test as the other 3 ports were drawing minimal power and had minimal data IO, it fits my use case and I'm glad that it worked out nice.
I know the advertised speeds are like 10x that of USB 2 but honestly, considering the overhead and all the bottlenecks, 3x speed is rather decent. Previously, I was using eSata, and got about 60MB/s, unfortunately, my new computer does not have eSata port. Others are also posting similar speeds so I guess that is about how much performance you can get from USB 3