I've been recently afflicted with this PCI passthrough stuff on one box (my smart new home ESXi) and the current state of play is:
ESXi 5.1U1 with all current patches - build 1157734
PCIe card passed through to a VM OK - it's a Sangoma telephony card 2 x FXO ports
DVBS2 USB dongle fails by trying to pass through the USB controller
That's exactly how it should be judging by previous comments. However I did some playing with ordinary USB pass through before I bit the bullet and wiped the box to install 5.0.
Initially I accidentally ticked the option for the USB device to follow the VM through a vMotion and performance was rather bad. Force of habit - I have many UPSs on the end of this style of connection for monitoring and it works well but a UPS doesn't exactly tax the USB redirector. I have now changed the connection to normal - ie add a host USB device to a VM without using vmdirectpath.
Performance is excellent for this particular use case - DVBS2 USB 2.0 dongle (Pinnacle PCTV 460e) connected to a Linux VM running a MythTV backend. From my front end I can watch full HD with no tearing or any other problems and crystal clear 5.1 audio.
I have not benchmarked anything and I won't ever be running a hard disk through this style of connection any time soon but it is certainly adequate for DVB receivers.