If the price is right, then, absolutely, a RockHopper would be worth buying. In their different incarnations, RockHoppers have been an entry point into mountain biking for over three decades now. Lots of fun has been had on them.
Yep, I've always thought of Rockhopper as their mid level bike (although that might not be true nowadays). £60 for one that fits and is not in immediate need of big repairs is good value.