I have a Casacius Bar that I mined directly to from Eligius. It's loaded with fresh new coins. (Eligius doesn't pay from a wallet)
From experience I have to admit it's harder to spend new coin haha!
What makes it harder to spend them? Do you have to wait for more confirmations than the six required for normal transactions? I didn't think there would be any difference between new and old coins when spending them.
Yes, the coinbase transaction takes 100 blocks to mature. (And the 6 transactions are not "required", btw. ;-) )
See:
Bitcoins that are distributed by the network for finding a block can only be used after 100 confirmations e.g. 100 discovered blocks. The classic bitcoin client won't display the coins earned for solving a block until there are 120 confirmations.[7]
http://en.wikipedia.org/wiki/Bitcoin_networkThe UTXO of a coinbase transaction has the special condition that it cannot be spent (used as an input) for at least 100 blocks. This temporarily prevents a miner from spending the transaction fees and block reward from a block that may later be determined to be stale (and therefore the coinbase transaction destroyed) after a block chain fork.
https://bitcoin.org/en/developer-guide