I use a Caldigit TB dock and it's working well.
Compared to the Belkin, the Caldigit is better because each of the USB 3 ports operate at the full 5Gb/s bandwidth. The USB ports on the Belkin only operate at 2.5Gb/s each.
You're right about the USB ports but I wouldn't say it makes it a better product, its faster for USB 3.0 yes but lacks firewire 800 which I still use for my audio interfaces. So depending on your needs one is going to have more pros for your use than the other!
And for the review there
http://fortysomethinggeek.blogspot.com.br/2013/11/caldigit-thunderbolt-station-docking.html
The review say that the usb 3.0 ports on the caldigit are not as fast as they should be. They don't go near the performance of the real usb 3.0 ports from the MacBook Pro which are at 5Gbps proof on hand in tests!
And the Belkin one is created so you can conduit the thunderbolt cable under and still be even on the surface its on, a feature the caldigit doesnt have.
Here is a french article (Sorry I speak french) It says that compared, the USB 3.0 ports from the CalDigit offer the same performance as the Belkin and Matrox thunderbolt docks.
If you don't believe me use google translate.
Les performances
Les ports USB 3.0 sont gérés, comme sur les autres docks, par un chipset Fresco Logic FL1100. Cette puce a l'avantage d'être compatible nativement avec Mac OS X. Sous Windows, il faudra installer le driver manuellement. Le FL1100 est capable de contrôler quatre ports, mais l’un d’entre eux est utilisé en interne, pour le codec audio. Seuls trois ports sont donc exposés à l’utilisateur. Quid de leurs performances ? Lorsqu’un seul port est occupé, nous avons relevé des débits de l’ordre de 350 Mo/s au maximum avec un SSD Samsung 840 Pro 256 Go dans un boîtier muni d’un contrôleur ASMedia 1042. C’est bien, mais loin du maximum autorisé par l’USB 3.0. Branché en direct sur notre MacBook Air de test, ce couple SSD+boîtier peut atteindre 440 Mo/s.
Le CalDigit Thunderbolt Station offre en fait ici les mêmes performances que les docks Matrox et Belkin, ce qui est somme toute logique puisqu’il utilise le même composant.
Translated to:
The CalDigit Thunderbolt Station offers here the same performances as the Matrox and Belkin, which is logical since it uses the same components...