1 Jax is not easy to counter with a banshee's. It's only the stupid Jax player who use W and then Q to boost up Q when enemies got banshee. They get countered, the other smart jaxes use Q and then W on enemies with a spell shield. That way the opponent only blocks 1 spell instead of 2 ;)
Other than that, good guide. But maybe add an escape echanism on Jax for summ spells.
If you are the carry you get focused all the time, so go flash or something is just fatastic.
Good guide, once again. :)

Read and try before voting, please :)