As I continue my quest to try out some of the most popular Chi-Fi favorites I just got the UiiSii CM5s. With just the silicone tips (per usual silicon tips don't give me the best seal, (my ear is weird I need foam tips to get a good seal with most IEMs).. my seal with silicone on CM5 is about 80%).. even still they sound very good, punching above their weight. Neutral sounding headphone. Vocals and highs could perhaps use a bit more clarity, but overall it's a pleasant sounding headphone. Also so far the most impressive accessories package. For $12 I paid you get tons of goodies. For an IEM they require quite a bit of juice to drive properly, I am driving them with my Schiit stack (on low gain), but compared to Tennmak Pros which I had on previously I had to up the volume quite a bit just to match Tennmaks.