I've had my x7i for about a week. I currently own the thinksound ts02,the apple earpod and the Alessandro ms1i.
Compared to the ts02, the x7i has a more balanced sound. ts02’s bass provides a good foundation but can be overwhelming at times. Ts02’s mid and treble are natural but a bit recessed.
The apple earpod is a surprise. Its sound is not as refined as the x7i and certain details and nuances obvious on the x7i are simply not present. Vocal also has a slightly hollow quality but otherwise the earpod is very pleasant to listen to and not much is lacking for a basic ear bud that comes with your iPhone 5 ( I paid for mine as an upgrade to the one that came with the iPhone 4S and I think it's worth the money).
i didn't compare the x7i with the ms1i because they are very different devices. I do find the ms1i's treble more open and natural. X7i's treble sounds a bit compressed at times.
One thing I do wish, contrary to some others above, is deeper and stronger bass. For some music, jazz or orchestral, something seems to be missing. I guess perhaps this is hard to achieve with a single armature driver. I had the same issue with the phonak pfe (grey filter. i found the sound with the black filter muffled) which I owned before. If I remember pfe's sound correctly, x7i actually does quite a bit better than the pfe in the bass but is still a bit weak in quantity, even compared with the apple earpod.
I am not sure if other tips will help. I got a pretty good seal with the large double flange as long as my head is not tilted up, so perhaps a better fitted tip can improve the bass?