Meh. It's not hard to ride! damn, you guys make it sound like it's extremely techincal and you needs lots of practice. Just ride it, have fun, It's a great bike and as long as you love it, you will have an awesome time. You got a great deal, now make the most of it.
Riding in the rain is fine, don't really get snow often in Tokyo, so can't comment on that.
I have ridden other frames sure, my first frame was a Langster Boston. that was nice and stiff and light, but I didn't like the compact geometry. Then I got a Bianchi pista. It flexed way too much. Then I got a masi Special Ltd. It was ok, but too heavy. I have ridden my friend's Nagasawa for a few days. It was nice, but too heavy compared to my Fuji. Stiff, light and fast. Have fun!