The trading experience is comparable to normal cryptocurrency exchanges except all the books are on the blockchain so you don't have to worry about exchange insolvency. You get yield on assets with high short demand like bitUSD or bitSILVER offering over 3% right now.
There is a powerful user-issued asset system, which flexible enough to allow traditional centralized companies can legally issue their stock, among a lot of other applications.
You don't have leveraged trading unless you want to leverage long BTS by shorting a BitAsset.
There are bridges to get from BTC to bitBTC to get in and out cheaply for small quantities, but the cheapest way to get a bunch of any bitAsset is still to go directly through BTS.
The fees are a fixed 0.1 BTS per transaction, or 2 times that if you are paying in a market-pegged asset with a price feed (so you can have just a bitUSD vs bitBTC balance and still pay transaction fees). There is not that much volume, but it is growing slowly as more gateways and exchanges come online and more traders from centralized exchanges see the utility of holding bitUSD and others.
It's theoretically more secure if you take care to secure your private keys. It's still risky just because it's a brand new codebase that has lots of bugs. Still not worse than Cryptsy though...
The math checks out on this guys, also the name and avatar.