I’m using already for almost one year the scm mercurial. Mainly because of Kiln tool that I really like to use on my personal projects.
Kiln is part of Fogcreek software and allows me as “start-up” to have a server account for two persons and keep repositories private. And also allows to share publicly some repos and to start to test it I l put my vim editor configuration ( a.k.a .vimrc ) available.
It is hard to talk about git vs mercurial but it seems that mercurial for someone alone or small groups fits better than git because it is relative easier to use. On my daily work I’m trying to introduce git and it is really hard to people that never used a scm understand all details and process everything around it. If I have choice, today I would start with mercurial and not git when dealing with small groups that never used scm.
About Kiln itself, it is really easy to manage and control the repositories, and use together with the Fogbugz tool. I’m not using the Fogbugz anymore since it is a bit overkill for a start-up but with Trello it is a good choice to start a typical start-up project.
In the end git-hub really became to me a kind a social network of code to me. The cultural behaviour on git usage also seems to fit better on opensource movement. they are two tools that works nice on their respective places.