I primarily play a 4 string bass, have played for over 30 years. I've had five string basses in the past but found the cons outweighing the pros in owning one. Mainly comfort in the weight, the wider fretboard more than anything as I have small-ish hands. As I play a lot of funk and slap, five strings seemed excessive given that slapping a floppy B string on a 34" scale bass didn't sound all that hot.
Well, as music tastes change, technology and choices for 5 or more string basses expand, after so many years - I finally found a five string bass I can see myself utilizing long-term. After playing for so long, I can usually tell if a bass is a keeper in a short amount of time. Funny thing is I wasn't really looking for a five string bass but traded a little used bass for it with the intention of playing the five string for a short while and flipping it. I picked up a very inexpensive Schecter Deluxe 5 for $150. I've had four string Schecters before, but models higher up the ever changing Schecter hierarchy. In other words, I wasn't expecting much let alone being a five string bass that changes my playing style and perception of 5 string basses.
It has all the qualities I look for if I were to utilize a 5 string bass- narrower fretboard than most, 35" scale so no floppy B string, a pretty light bass especially for a five string. I've had much better 5 string basses in the past, but it felt like it was more of putting up with issues than actually liking the particular basses. Well, I do like this cheap Schecter bass and can see myself switching over because of it - go figure.
I don't see any con with playing five/six string basses as long as you have the desire to do so and the right kind of bass that will fit your needs, extra strings = more options.