Managed to pick up this dock super cheap!! It works with my iMac 2011 27″ and MacBook Pro 2015 13″. (Technically it also works with my iMac 2015 27″ but that already has 4 USB slots!)
Quick review on youtube
Gives a really good USB 3 upgrade to the iMac and extra ports for the MBP.
I found a guy selling many of these and most of them went around $200, but I got mine for about a third of that because it has minor blemishes.
I’m now looking for another one for a similar price, $200 can buy an iMac, so I’m not gonna spend that on a dock!