Need to make a decision.

Background: M&P Shield 9mm personal weapon. I am US military (stated to imply experience with the M-4), trained with M-4 and all crew serves.

Considering -an Assault Rifle- a semi automatic rifle of sorts.

Can't decide between AR, Tavor, and AK.

My primary concerns are affordability, practicality (alternate home defense weapon), and fun. In that order.

Edit: Sorry for triggering everyone by explaining my training and writing "Assault Rifle" my
/sincerest apologies.