DOA4 still looks really good. DOA3 unfortunately has aged to the point where a lot of stuff looks blurry but the art direction is still solid. I also really like Ayane's default DOA3 costume that TN annoyingly dropped for that silly bright purple ninja suit.
I feel that there is a lot to be learned from the games in general, even if they are not the best gameplay wise or artstyle wise, i'm just mad i can't get DOA 3.1, since is the one people seem to really love, and also that sick ayane cover.
Why can't you get 3.1? It's easily the best of all the old titles. You can just import a copy from eBay. They're really cheap. I have two copies myself.
And @Force_of_Nature, DOA3 still looks fine. Maybe it looks blurry due to your TV setup. When I run it on my OG Xboxes with component cables, it looks fantastic.