Ok, my thoughts after watching the first two practice sessions.
1) Sound. It's really decent, nice, and yet has it's special characteristic. Well, passing-by sound is not that spectacular, and much less noisy, but that turbo sound at braking points partly covers that lack of V8 roaring. Meanwhile, an onboard sound is another talk - it's as powerful and characteristic as V8 onboard sound, just in its special way. I find that lower range sound a bit more powerful that V8 high range sound.
2) Dick noses. Well the title says it all. In terms of aesthetics, the cars are silly now. Well, it was already widely covered by media and fans, but seriously what the hell with Lotus fron wing, for an example. Still a mystery for me.
3 Performance. It's looks like Mercedes are a team Nr.1 currently, meanwhile the second is Ferrari, third Williams, and 4-th place is between McLaren and Red Bull at his moment. I think Red Bulls all that fuss was for nothing. They definitely ain't that bad, as described themselves before the championship kicked-in.
4) Rookies. Kevin Magnussen clearly feels the pressure, yet isn't well comfortable with the car, as long we can see him drive at least 0,5 sec slower than Button, and drives often off the track. Daniil Kvyat did not impress me with his driving this morning. A lot of off track driving, can't even simply let other drivers pass him. He is very strained and a bit lost in the traffic. Hopefully he will get better.