how is the mix ? anything I should look to add from first expansion ?
Well, I usually advise "one of everything", just for variety's sake. There really aren't all that many pieces (you're only missing 5 from the first set), and at this point they're fairly cheap. After a few games with what you've got, you could try making up some proxies for the missing pieces (the stats are on www.naviadratp.net) and see which ones you like.