I vape all different nic strengths. From 48mg to 8mg. It's all about the enjoyment of the flavors IMO. Once you get the other additives from analogs out of your system, nicotine content matters a great deal less.
For that first month of jumping off the junk, I tend to see a lot more people have success when they use a higher nic. 24 is what I recommended to my friends, regardless of what they smoked. Once they feel that first clean head-buzz, the speculation on whether vaping is some placebo goes away. After that, lower or raise to your preferences. Keep a stronger nic around for the times you want to break down, and a lower nic for times you just want to enjoy the great flavors of the many e-liquids out there.