The Marushin M629 is a worth replica as it certainly looks the part and could deceive people into believing it's real, though we wouldn't want anyone to attempt that feat.
The M629 is a Black Heavyweight weighing in at about 932 grams and with its Matt Black finish, it certainly looks and feels like you're holding the real deal. However, shooting it is a different situation.
Airsoft guns coming out of Japan are not the most powerful as they do have a lot of restrictions. This one fires at 200fps with HFC Gas and 250 with Green Gas. This is something we can only find out since we're out of Japan. It's relatively accurate but I wouldn't say what appeals to most of us.
It may not shoot how we want it to shoot, but it does look incredibly beautiful, with its 6 shells as it's something collectors could add to their Airsoft Arsenal. Maybe even use in a game!