There's a couple of pfSense subtopics, so check them out.
It's the little brother of the SG-2440, two less ports, 2GB vs. 4GB of RAM on the 2440, and it's fairly realistic to expect it to handle a 500Mb/Sec pipe with little effort...
The smaller 2GB RAM footprint might impact Snort performance, if one wants to run Snort (many do)...
As far as uptime, most folks only reboot on system updates, generally they're very stable - as for build quality, they're first rate, but a bit spendy compared to other options.
pfSense does have a bit of a learning curve, esp. when doing things like building port forwards, dmz, and the like, but there's a lot of power and capability inside pfSense.
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