There was an issue on 2.5.x that was broken for a year where dummynet was sending traffic to a blackhole on WAN interfaces but mysteriously was fine on LAN.
Then they had some kind of code crunch just before the RC and they fixed it in one direction, sadly its still broken on inbound traffic but pfsense still consider the bug fixed as almost everyone uses it on outbound matching only.
Having been using 2.5 for a year in a datacentre, that was/is the only problem I had with it.
2.5 is a bit of a unknown, as some who may not be aware netgate are now going to focus on their commercial product which is forking away from the community edition, they will still offer code contributions and still supervise the project, but as to how much attention it gets moving forward only time will tell.
I will be testing the commercial product on the dummynet bug as I am curious if that will work on there.