I've been running pfSense since around version 0.31 (alpha days) and even ran a mirror for them for a few years.
Your microserver is way overpowered for it though (unless you're on hyperoptic or something...). I have it installed on a first-gen Atom mITX board, single 1.6ghz core, 512MB of ram with a couple of 100mbit NIC's (yeah, still limited by my 80/20 FTTC anyway.. heh) and maxed-out grabbing a linux ISO torrent the cpu usage is well under 30% and its a pretty damn slow CPU by anything today's machines have.
I've found to to be rock stable even since those early days - not that at the time I was asking a huge amount from it.
Features wise its pretty up there with some of the paid products, and with the packages system you can really extend that functionality further. I've used it for a few different connections at home over the years. This has included routed /29's, native ipv6, tunnelled ipv6 (boo Zen, gief proper v6..). Dynamic and static addresses too. It's really happy doing it all.
These days I have it running a couple of permanent OpenVPN tunnels to a couple of different work sites so I can access the remote networks from any machine on my network without additional configuration, and it also runs an OpenVPN server for me to dial in when I'm not at home.
I've got a few friends who tie entire corporate networks together using it, and even one using it to run a small ISP for users in a block of flats using its PPPoE server. Really can do pretty much anything you throw at it, whether its home networks or multi-gigabit routing. Just need to scale the hardware suitably.
Whether it really gives you any more than you actually need (and currently can get) from your Draytek.. only you can answer that.. but I can say for sure pfSense is a safe bet if you're looking for something low-cost but very capable.
PS. If you want a more compact home for it to run on than a microserver, there are some nice products on LinITX (for example) with 3 GbE ports in a metal chassis which are fully solid-state industrial-style computers. Which also happen to ship with pfSense preinstalled..
Edited by summat (Tue 09-Dec-14 17:57:54)