The Remington 770 might not be all that good of a rifle in comparison to more expensive ones but it really is a good rifle for the money.
The 770 is not a good rifle period
. In absolute terms it is a steaming pile of junk that makes a BIC lighter look like a solid gold Dunhill.
In relative terms there are lots of better rifles available for similar prices. The few dollars it might cost to step up to a Marlin X7 or a Savage Axis would be the best you ever spent.
I wouldn't own a 770 if it were free.