MONDAY 2ND DECEMBER 2013
“Waiting for the 2.5 min LTC block is only 1/4th as secure.” – Erik Voorhees
That’s actually false. There’s a long math-heavy explanation about this in Bitcoin Magazine (issue 13 I believe); essentially, if you try to actually calculate how secure N confirmations are against an attacker with X% mining power, the chance of success can be calculated to be (X / (1-X))N – the block interval shows up nowhere in the calculation. Hence, six 10-minute confirmations and six 1-minute confirmations provide essentially the same level of security
One of the major use cases of Primecoin (1 minute block time) is actually that it lets you move money between exchanges for arbitrage very quickly, as exchanges wait for 6 confirmations for security. Also, many websites (eg. SatoshiDice) wait for 1 confirmation before acknowledging a payment, so Primecoin and Litecoin win out somewhat there.
All in all, I think altcoins are fine at the relative price level they have toward BTC – Vitalik Buterin