Yum!
Yes, the smoked meat sandwich is worth all of the hype and yes, you should get a pickle.
I'm not keen on queuing so I grabbed my sandwich and pickle to go and ate it at Mont Royal park instead. The meat was super tender and flavorful and it's true that just a swipe of mustard is all that the sandwich needs. The bread was fluffy and soft but somehow withstood the hearty meat. The pickle was pretty standard (typical Kosher pickle) but I loved it even more because it helped cut through the unctuousness of the meat.
Honestly, this is better than Katz's.