Nice Graphics (after HD update) and good gameplay, but a letdown in some of the aspects.
Gameplay: 8
Sound: 5
After the Runescape HD update, the graphics now are solid and not half bad.
The gameplay is the best of the categories here, because there are a wide variety of things to do (if you're a member), and provide up to some limit to free players. But still, I am satisfied by the range of the things that you can do.
The sound is bad. The only real sound you get is music, and even if you have sound, it sounds like gibberish. Weapon and armor sounds effects are not bad, because you get different sounds depending on the weapon and armor. But aside from those, it's all gone.
But is membership credit worth it? I'd say yes and no. Yes because you get to explore the full potential of Runescape. No because there's too much to do in just little time, and the $5 might not be worth it in some areas.
But basically it can keep you busy and it's better than nothing, so I reccommend you to try it if you have nothing else. There's a lot more better things out there. But there are worse, too.