3DAce is interesting in that respect. Without being a spline modeller, it provides all the basic splining techniques of A:M (except hooks and five-pointers):
Cage drawing (similar to the add point tool)
Generating triangles and quads (unlike A:M, it's only semi-automatic)
Fusing points by right-clicking during a drag
Connecting edges one by one (as in the add point tool's split-me-slowly mode)
Running a new loop through an edge ring (a plugin in A:M)
Cutting through edges (again, a plugin)
Removing a loop
And it also offers good interactive symmetry and edge/face selection, both of which would also fit in with A:M's toolset.