Obviously I can google this, but I would just like to hear what you guys have to say as those articles are outdated and may contain irrelevant information.
If you are a bitcoin's price trading guy then try out BTC-e I always have used them and they never disappointed me at all. Though they have a rule I guess that when you make a new account and deposit money you cannot withdraw till 24 hours, though this maybe for security a new guy joining may get worried.
Other than that I would say there are sites like poloniex, etc for altcoins trading and are quite nicely running till now.