i dont see a reason for a 4 string anymore...the only reason to have it is if you cant play a 5 or a 6. Which only means you have to work a little bit harder but in the end you will have a wider range of sounds you can get to....i dont see the the reason for 4. Personally i would like to upgrade to 6. i have a 5 and its decent but i was playing a 6 string and i realized i can really utilize the 6 strings.