If you are using MLT with the DVEO (formerly Linsys) SDI or ASI cards on Linux, you should know that the drivers stopped building somewhere between kernel 3.0 and 3.2. The Open Broadcast Encoder project made some simple fixes available on their github repo.
Shotcut is a new application from the lead developer of MLT. It will eventually become a full video editor, but currently it is just a media player. The emphasis of the work thus far has been to develop a solid foundation - both code and project - upon which to build and iterate. To learn more, head on over to its website.