IVAs are not a "government project" ! Did you hear that from a politician, or some IVA company's advertising ?
They were set up with the Insolvency Act 1986 to offer a more controlled realisation of assets for debtors in difficulties, initially envisaged as being for business debtors to enable the business to continue trading to provide funds to repay debts, as they can be far more flexible than bankruptcy.
It is only really on the last 5 years that they've taken off in a big way to settle consumer debt.
If you enter into an IVA, then it will show on your credit file for 6 years and you won't be able to obtain consumer credit during that time (acutally you wouldn't want to take on further credit anyway).
Don't enter into an IVA if you don't feel you can maintain it. You will only obtain the benefit of any debt write off at the end of the IVA if you have stuck with it and it completes successfully, if it fails after 4 years, all the debts that were in the IVA will get resurrected and you will again become liable for the whole remainder of the outstanding debts.
Before your IVA is in place the creditors can issue default notices, but so what, a default notice is just a waste of tree, it won't have any effect on whether your IVA gets approved or not, creditors will vote according to ehether your repayment plane seems reasonable and manageable or not.