Too often. While it has happened many times before as I have read recently, I noticed it only once.
I would love to find another way to take bitcoin automatically using opencart.
chreck this out may help
https://en.bitcoin.it/wiki/Category:EWalletswhen you saw MyBitcoin down how long was down 1hour, 1day, 1week?
I thought it was a day.
Ewallets are really not the issue, it is the shopping cart integration that they provided. Others are working on it but I currently know of no other solution for opencart.