So I bought, tried out JB+ camera on my RHD indoors last night. It's not very impressive but seems worth 2 bucks so far. It seems better in getting consistent color and exposure at least.
The Moto stock camera app is doing very poor job in white balance when lighting is less than ideal. And it's very unpredictable. Sometimes it's casting blue tone or orange tone and I have no idea how the color will turn out. Metering seems unstable at times too, as some shots are too dark or too bright. But compared to stock camera app, JB+ seems more accurate and stable in white balance, exposure. This is good improvement.
But in terms of focus/sharpness, I see very little to no benefit from JB+. Compared to lucky, sharp images from stock app, JB+ maybe slightly sharper. And it takes quite longer to get first focus lock after opening the camera app. After that touch focus seems ok though. I feel like getting focused image consistently is better but this needs more tests to confirm. I will do more testing outdoors and update my review if I feel like.
Overall I agree with Crewville's review. It doesn't turn poor Moto camera to great camera suddenly. But it made camera more useable now. Probably Moto X camera is better, but if you are unhappy with camera I guess Camera JB+ is worth trying.