Good discussion going on here. Will just share my recent experience with you all. As some of my IJC brothers know, I was going for a engine swap last month on my BJ60. the choice of engine was 2F, while currently running a 3B which gives me good power for offroading and good fuel economy for daily driving (9km/ltr). Whereas a 2F is not so good on mileage and the carbi issues, although can be worked out, still requires you to spend time at the shop. Moreover, with fuel prices going crazy in Pakistan, a 3B will definitely give you more kms/ltr as opposed to a 2F. No doubt the 2F sounds like a more fun engine to play with, but not for a daily machine in terms of practicality. But if you have a project machine to play with, then go for it. I was also advised that 3F is a better option as opposed to the 2F for obvious reasons.
I was at the brink of making the swap to 2F, when I realized that 3B is the better engine for my specific requirement of being a daily driver + offroading machine.
In the end it simply comes down to what your requirements are for your machine and how you want to use it. In my case, because I use my BJ60 daily, I decided to stay with my 3B with plans to put in a 5-speed transmission as opposed to the 4-speed that im using now and maybe later throw in a turbo.