I got a pair of ws55's and liked them but they got into an unfortunately accident! So I decided to get another pair, as I was browsing I found a couple of reviews of the ws55i stating they sounded better and for and extra £8 I thought might as well, and its was true the bass was the same but a tiny bit tighter, and midrange was a tiny bit crisper and top end was brighter. I was shocked that they had improved them while putting on a mic and volume control knob, but then the rrp price was £30 more. I got mine on ebay for £62 inc shipping, and as far as I am concerned you will never find better phones for the same price or less, they perform to a imilar level of £100-£150 phones (bear in mind I am a bass head). What I will say is that the bass does not overraw mids or tops, and doesn't come with that dull muffled sound that cheaper 'bassey' phones tend to produce which might be why the original poster thought the bass was weak.