The x889 has more features that allow you to customize the sound to your liking, such as digital time alignment, cabin size and type selection, and speaker size. It also has a 4 band PEQ with adjustable center frequencies, and decay rate. Another advantage is the fully selectable xover points. The x889 allows you to choose low pass or high pass at 40, 50, 60, 70, 80, 90, 100, etc up to 220 I think, with individually selectable slopes of 12, 18, or 24db. The eclipse only allows certain freqencies on low/highpass, like 63, 80, 100 etc.
The eclipse does have its own form of SRS WOW, which the x889 has as well. I can't imagine the eclipse sounding any better than the x889, given all the extra flexibility the 889 has. Also, with x889, you can remove your faceplate! //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif