Is the gearing *exactly* the same? I had a moderate amount of difficulty when I got my custom Guru, as compared to the Kuota. While the Guru actually has 2 lower gears than the Kuota, it does not have some of the same gear combinations. I felt that I was either in a gear which was too easy or hard, and had some trouble finding my comfortable place. I sucked it up for about a year, and finally my average was about the same on both bikes. I am very sensitive to any change on my bikes. Like if something is off 1 cm, I will know it. I can handle 1-2 changes, but every step for me means ingraining it in my muscle memory for quite a while, before it becomes second nature, if there's a lot of steps involved. There have been a few things that have been intuitive for me, like clip less pedals and shifting, and I gues that has helped me that those are big things, which often trip people up.
Putting 25 cm tires on my Kuota made it feel more stable, and since I already had them on my Guru, I made the switch last summer.