Just a FYI: Litecoin does NOT confirm faster than bitcoins. Based on how the core bitcoin protocol works (which litecoin does not alter), a halving in confirmation time is also a halving in reliability of the confirmation.
If an attacker does control 50-plus percent of the total mining power, you're basically screwed. Increasing the total confirmation time doesn't increase the cost of a 51% attack by enough to be worth attempting.
Given that btc-e has a lot to lose on double spend attacks I think it's a good measure of how these two currencies are playing out in the market.
If blocks are too fast you start getting very large reorganizations.
Today litecoin has almost no transactions, so its lower interblock time is not a problem... Yet.
The reduction in time to perform a 51% attack is countered with just a few more conformations.