Replay Media Catcher can record MP3 and FLV files through the HTTP and RTMP protocols, while FLV Recorder can record FLV files only.

They use different ways of capturing RTMP packets. FLV Recorder uses winpcap while Replay Media Catcher works more like a firewall.

I prefer the support of Replay Media Catcher. Mostly because of the native english speakers with fast responses.

Besides Replay Media Catcher has a 30-day money-back guarantee. It means a lot to me.

Both programs are free to try so you may compare them without paying any money.