I use 28g 2.4mm 8 wraps 1.4 ohms on my KF3.1's and am liking 26g 3mm 9 wraps 1.24 ohms on the KF4. 27g 2.4mm 9 wraps 1.2-1.3 ohms was good on the KF4 too, but 27g is an odd one and most people won't have it. I only do because it was sold to me as 28g.
The worst KF4 coil I tried was 28g 2.4mm 7 wraps 1.2 ohms, I found not enough surface area for the larger airflow and a dry, muted taste. But fewer wraps are working for others, so it's certainly an individual thing.
I certainly think the KF4 needs a larger surface area and larger diameter coil, and a bit more power than previous KF's.
Re the questions on whether to buy a KF4: that depends on expectations and funds. If spending $200 ish over $100 ish for a KFL is a big issue or you can't afford or justify an extra $100, then it probably isn't worth it. I wouldn't say it's twice as good in all areas to warrant twice the cost, if that's the way one looks at things.
If you want one however, and $200 ish won't break the bank, then go for it! You're unlikely to regret it. If you don't like it, you can always sell it for close to what you paid; it's not as there aren't plenty of potential buyers at the moment.
The taste is on par with the KF3.1 / KFL. Some say better, some worse. I think it's extremely similar, if slightly different. Some flavours will be slightly enhanced, some slightly muted. Filling is much easier than previous KF's and leaks are extremely minimal. If you like more airflow and lower ohms than is generally within range of an earlier KF, then definitely buy a KF4. It's far more versatile than previous versions.
All in all, I'd encourage people to buy one, especially those who like Kayfuns or would like to get into building one, whilst remembering that everyone has different tastes, desires, and expectations.
Everyone's different, each has his/her own tastes and priorities ~ so how do we fit two in the same template?
