the current 3dgs newton plugin uses a very outdated version of the newton engine. i am currently working on a new plugin which is up to date but it will still take a while. if you don't want to wait you could do your own wrapper.

newton is faster than ODE's big matrix solver but slower than ODE's linear solver (which isn't stable enough to be very useable though). 3dgs uses ODE's big matrix solver by default.

newton is more robust and in the meantime also more feature rich than ODE (i don't want to start a flame war, even ODE's author is aware of and admits ODE's shortcomings).