SharePoint 2010 - How to check if SPGroup exists

I've tried to check, if a SPGroup exists this way:

string nameOfGroupToCheck = "My SPGroup";
if(spWeb.Groups[nameOfGroupToCheck] != null)
{
...
}

...but this causes an exception, when the SPGroup is not existing.
Try this one:

string nameOfGroupToCheck = "My SPGroup";
if (spWeb.Groups.OfType<SPGroup>().Where(g => g.Name == nameOfGroupToCheck).Count() > 0)
{
...
}