Recently I’ve been playing with Autodesk Fusion 360. They provide free licences for personal use, which is very nice from them.
The software is really, really, really great. Here are the features I like the most : clean UI, possibility to return and change dimensions of bodies, joints.
The only drawback for me right now is that you need to store all of your design in their cloud.
Here is a simple example I made (even the embedded viewer rocks !).