I built a 60% keyboard today from a kit. I'm still adjusting to the lack of arrow keys, home / end / delete keys, and a numpad. I think I will find this easier to use over time, but the learning curve is greater than zero at this point. :-).
In addition to the loss of some keys, I upgraded (in terms of typing weight) from Cherry Blues to Gateron Greens. As I hoped, it is a more satisfying typing experience. The verdict is still out about whether I have any finger fatigue from the extra effort.