I liked QFG5. It’s not as good as the others, but it was still good. The only complaints I’d have are that it’s the last one and I didn’t want the series to end, I didn’t like the giant overhead map style of exploration (I didn’t like it in QFG3 either), and the fighting was seriously flawed. I wish they kept and expanded upon the original style of fighting (pre-QFG4).
As for KQ8 and GK3, I liked GK3’s story and that’s really what I played it for. Well, I liked it up until the end when it turned into Indiana Jones and the Last Crusade. I only played KQ8 for about an hour and then got sick of it. I thought the graphics were horrible and the gameplay was boring. The draw distance really bothered me. It’s hard to be immersed in a world when it’s nothing but fog in nearly every direction. Or maybe the graphics just don’t translate correctly on new video cards. I tried using a glide wrapper and I don’t know how to play it in DirectX. Out of those series finales, QFG5 was definitely the best.