Depends on what your using it for? For 3d printers I like FreeCAD. Though it has a bit of an initial learning curve. It has a lot of functionally. SolveSpace was pretty good but I had some trouble with fillets and things. Might have been user errors… I havent used blender much but heard its good for more artistic modeling for games and videos. Not sure if it would work good for 3d parts? Anyone use it for that?