I wonder what that overkill in speed is for. With serial ports you don't need that much bandwidth (48 ports x 100 kBits = 4,8 MBit/s, yes I know it's 115200 but too drunk for math). You could even run that thing with a 10 MBit/s LAN interface.
The only thing I understand is the PCIe stuff because USB latency can be problematic (especially on the Pi).
The problem with them is that they use just an 8051 microcontroller (talking to an ethernet controller over a parallel port)! Arp and other broadcast background traffic on modern networks overwhelms them.
The Broadcom Trident 2/+ chipsets, that a lot of vendors use for their merchant silicon, only support 1, 10, and 40 gig PHY's. No more 10/100 on these switches (which are all over every datacenter).
As the poster below said, GbE is mandated by a lot of data centres. 2 ports is also pretty useful too - you can aggregate them if you're concerned about reliability, you can use the console server to segment out a management network etc.
I wonder what that overkill in speed is for. With serial ports you don't need that much bandwidth (48 ports x 100 kBits = 4,8 MBit/s, yes I know it's 115200 but too drunk for math). You could even run that thing with a 10 MBit/s LAN interface.
The only thing I understand is the PCIe stuff because USB latency can be problematic (especially on the Pi).