I have been using jRiver exclusively for a few months now. However, I was intrigued by a wijnand’s post regarding Twonky in another thread (http://www.psaudio.com/forum/#/discussion/comment/62124) and I tried Twonky Server for Windows. The sound is definitely different! Twonky sounds darker with a cleaner soundstage, more colorful and emotional vocals. It’s like some not-so-clean highs are removed. I cannot say that Twonky is hands down better. Some recordings sound better with jRiver. I have only spent less than an hour so these are just first impressions. I wonder if anyone else bothered comparing these tools.
BTW, this is not clear from their website, but the Twonky is available for trial download: http://twonky.com/downloads/.