My experience of FWR coincides a lot with what Arch said above.
There are a lot of feminists of one particular persuasion here, namely radical feminists. The first discussion I ever waded into was on transgender, and the transphobia expressed by a lot of posters was, frankly, mind-boggling to me. I still find it disturbing. Yes, there are some hateful transactivists out there, but they are a tiny minority among transgender people, and the amount of time and energy certain MN feminists devote to condemning them is a mystery to me.
I also learned that lots of MN feminists find terms like 'cis' and 'gender identity' offensive and oppressive. That surprised me also.
It was my first encounter with radical feminism outside of books (I'd read Dworkin, MacKinnon, Chesler, etc) and while it was educational, the transphobia in particular really put me off, as I said.
I also believe that prostitution and pornography are complex phenomena, and that radfem views don't often take this complexity into account.
My feminism is very important to me and I can imagine engaging more with the FWR threads if I had more time (I would probably just avoid the trans threads). But I would also be tempted to engage more if FWR were less dominated by the radfem perspective. I certainly don't blame radical feminists for dominating FWR; I mean, anyone can post there, and if feminists with different perspectives did want to post, there's nothing to stop them from doing so. The radfems are clever and articulate and I can find plenty of common ground with them... it's just that I don't normally read an FWR thread and have a sense of coming home, IYKWIM. There are a few regular posters whose perspectives seem much more akin to mine, but they are definitely exceptions.
Nevertheless, as others have already pointed out, you can find feminism in action virtually everywhere you look on MN. Some of the relationships threads are amazing.
I will retire now in the hope that I haven't alienated all the FWR posters forever. 