I've been using the old Mozilla suite before for a long time. So I'm quite happy that SeaMonkey took the legacy and is developing it into something even better.
I like it's completeness and as a browser I find it just as good as any other. My favorite is the default mini-preview for tabs. It's nicely configurable. Memory usage is still good even if using mail client and browser at the same time.
Long live the alternatives, so I highly appreciate what SeaMonkey developers do to preserve and enhance it!