I essentially did the same. Used GNOME for almost 10 years, then got my first try of KDE last year and don't plan on going back either. GNOME has some really good points, I wouldn't have used it so long if it didn't, but I can actually use an honest to goodness theme on my desktop and customize without having extensions break on every update. Also, the UI in GTK is just too big and chunky for me, it's like every window is designed for tablets or something. I don't need a title bar that's practically an entire inch tall. If you like GNOME, awesome, I will likely never say GNOME is bad, but I'm a KDE guy now.
EDIT: apparently I need to specify that the "entire inch tall" comment is exaggeration, because internet. My point being that GNOME's UI is too big for my tastes.