If you have the right coils the Crown II is incredible , the RBA kit is the best i have ever used . What kind of issues can you be having , you do have to prime the factory coils more so than the original Crown and make sure you start new coils at low wattage .
Never start coils at high wattage especially when new and breaking them in, even if they are primed .
I haven't used any of the RBAs, in my original Crown i prefer the .5 ohm coils, and when they work, prefer the same in the Crown 2. I prime the coils, usually let it sit for at least 30 min, usually longer before even starting to vape, and I start around 20 watts and slowly work up from there. With the .5s around 50-55 watts seemed to be my ideal range, on both Crown 1 & 2. With the Crown 2, its great for about a day (if that), and then it's just dry nasty hits from there. I've also taken a pin and poked the cotton through the juice holes. That will help for about 30 min, and then it's back to totally inconsistent performance with a lot of dry nasty hits. I've tried about 4 different coils for the Crown 2 and all have been the exact same way. Curious to try the Rafale coils in it though. I'd be totally happy sticking with the original Crown tank for a while if it only didn't have the issues with the whole tank coming apart when trying to unscrew the top cap. The Crown 2 design definitely fixed that with that locking mechanism, and I prefer the look and design of the Crown 2, I just wish I could get the same performance and flavor out of it as the original Crown.