My tree usually has the most complete information for my direct family because I've bought all the certificates and only used confirmed sources, never word of mouth. I am offered lots of matches that do seem correct but the information isn't as full as mine. What happens if I confirm a match? Is my information replaced by the information on the other tree? Coz frankly, 90% of the time, my info is best and I don't want it overwritten.
No, your information will not be replaced and you can always undo the confirmation
Before you confirm you should choose to read through the match and also choose to compare the match showing it in bouth trees. Then you might find more information from the other tree.
If the match is obviesley wrong and you don't have any other matches on that tree, my adwice would be to dismiss the tree, not only the match. Then this tree will be placed at the bottom of the list of smart matches. You can always undo the dismissing.