Some years ago, I bought a KMS104 (cardioid), and was immediately impressed with the sheer detail and delicacy of the sound I was able to get. I chose cardioid, since most other vocal mics I had were cardioid, and I wanted to avoid the "rear lobe" that some super/hyper-cardioid mics exhibit. Anyway, I was pleased with the 104 but have found that I sometimes struggle to get wedge monitoring loud enough when using it.
I decided to try the KMS105 as an experiment really, on the basis that it was going to be as good as the 104, but would hopefully be better from a feedback point of view. I was right! The 105 IS a much better betif you're using wedges rather than IEMs. The sound is still wonderfully crisp, but with a rich body as well, just like the 104, but I find I can get all the level I need from monitoring, even on "loud" stages. There is a rear pickup lobe, but to be honest it's not noticeable, and certainly have never been an issue.
It is now my best mic, and goes out on every gig where there is a decent vocalist. I plan to sell the 104 and get another 105, because for me, it's just that bit more useable.