As antenna I've used the HP Omnidirectional Dual Band MIMO antenna (J9659) which provides 3 connectors per band for maximum of MIMO 3x3 configuration.
Power consumption (according to PoE on switch)
without miniPCI cards: 3.3 W
one card turned on: 6 W
both cards turned on: 8.2 W
during normal operation: max 10 W in peaks
So the 802.1af capable switch is enough to power it. We also use Cisco AIR 1240AG which is 802.1g dual band AP and it consumes around 10W. Which means RSPRO can deliver the same or even better for 2 Watts less power.
Boards BIOS boot in less than 2 seconds, the clean system can make it in 20 seconds and with full configuration for our environment it takes around 35 seconds. Throughput of network layer is only limited by the wireless standard because all metallic ports on the boards are gigabit. So even with two cards set to MIMO 3x3 with maximum of 450Mbit/s I should not fully saturate the gigabit link.
There should be no major problems except of occasional crashes of system not handling something which results into automated reboot of device (thanks to the watchdog). Maximum observed number of connected users was around 60 (45 on 2.4 GHz radio and 15 on 5 GHz radio). Mean time between reboots is 2 months in environment with around 5-15 users connected every working day.
Main drawback of this affordable and nice configuration is that RouterBoards
are in EOL (End-of-life) status and as of summer 2012 they are generally not
available in large amounts (some last pieces may be still available somewhere)