any exchange like mcxnow and altcoin investing?

[MMOPoker]

Unfortunately mcxnow closed down and i'm wondering if there are any reputable btc/altcoin exchanges out there.Can anybody also give a ruff estimation and likeliness of getting a return of +15+% year by holding on to altcoins?

[LiteCoinGuy]

bitstamp
btc-e (alt)
coins-e.com (alts)

problem is: its wild west and a young technology. if you cant afford to lose money, you should not trade at all.

[HigsonPP]

reputable? good luck.