i used the beta about a year ago, and just redownloaded it to see how much changed. It's still too focused on interface looking good over providing real functionality. The screen sliding is annoying, much worse than similar effects on OSX.
The default interface is one of the must unintuitive pieces of eye candy i've seen in a while. With every other player, they manage to keep basic controls (play, stop, volume, etc.) together in an ordered pattern, and they're all instantly recognizable. Not for Sonique; some buttons are clustered, some are set in a line and you have little idea what they do until you roll over them. i really can't be bothered to even install other interfaces when the main page links to a forum that doesn't even have previews for many of them.
i do kinda like the way the options are handled, in a web-style hierarchy, although i have to wonder if they could've grouped some things together. Also nice is the option to stream files to the hard drive, but it would've been better if they just made it a record button instead of... whatever it is.
i really have to wonder why other companies even try any more. Winamp, WMP, RealPlayer, iTunes, and Foobar (did i forget any?) really have it wrapped up in the PC audio player market.