I have been using a FC660C as one of my daily drivers for a couple weeks now. I have to say that the some of my favorite things about this board are not actually topre related. I find the arrow cluster to be pretty close to perfect for me. I love the way the ~ is handled on this 60%. This board feels solid and is a pleasure to type on, however I am not finding topre to be the ultimate typing experience for me. I go to the office some days and actually look forward to my browns because they still make me happy. I like a really light key, but with a tactile bump. I am finding 45g topre to be little heavier than I like. It is possible that a topre board will break in really nice, but right now it is a little heavier than I find comfortable. It may not even be that they are heavy as much that I can't stop from bottoming out on them and I think I am finding the jarring from that to be fatiguing for my hands.
Once I build a 60% or 75% MX board, we will see which one stays as my daily driver at home. I have to admit. When I had the topre next to the mx switches, I always chose topre. I think that might have had something to do with it being new. I actually took my browns to work in order to guarantee time on them. The feel of the switch is hard to describe, but it really is an amazing experience. I just have a hard time with it for long stretches.