This isn't new Bitfinex has been around for months maybe even a year. Sure maybe ltc trading is new but other than that nope. I'd rather trade with BTC-E's Metatrader 4 platform (3:1 leverage) which can buy and short. Not to mention they have tons of pairs to choose from not just btc, ltc, and usd. Metatrader 4 is the most professional trading platform currently offered by any cryptoexchange because it's the same platform used by thousands of forex (currency trading) brokers and traders around the world. AND the best part is you get all of the most popular of indicators to trade with or can build your own in MQL4 language. Alternatively build a automated trading script called expert adviser. *Automatically trades based on preset criteria as long as mt4 is open*
Most importantly though with BTC-E you don't have to submit any personal documents (KYC). Either way 3 or 4 to 1 leverage isn't much to work with. Personally I'm still waiting on 10-50+ :1 leverage broker.
You don't have to submit any documents with bitfinex either. The only time you submit documents is when you need to wire USD in or out of bitfinex. Other than that you can buy / sell btc/ltc and transfer it out freely.
Also one key thing that bitfinex offer is a great lending program. Awesome to lend BTC/LTC that are just sitting there...