I have used AutoCAD for years and have tried several Cad packages such as Draftsight, Progecad etc.
I have recently started using Librecad and am generally pleased with it.
However, there are some points which I find very frustrating.
1) When drawing a line I would like to be able to select a start point and entry a length in the direction of the cursor. This is a feature of many CAD systems and is very useful.
2) I would like to be able to save drawings to DWG files.