The biggest issue I have with Fortinet is that they're releasing FortiOS with new features before it's ready. Now we have like 4 trains of FortiOS and all of them have bugs one way or another. Lucky for us I turned off SSL-VPN back in December when Fortinet tech support refused to issue a patch on an older FortiOS V6.0 as I wasn't ready to upgrade from V6 to V7. Ironically enough they did released a patched version of FortiOS v6.0 the other day for this vulnerability which I was able to apply.
If Fortinet keeps this up and with their ever high prices of their security subscriptions I will be forced to look for alternatives.
I've deployed several Netgate's pfsense appliances for remote offices and been happy with them. I use pfSense at home as well on repurposed Dell desktop PC.