The same can be said about Bangkok (the part about being good for "a single guy looking for...")!! Even Singapore is the same-- I lived in Joo Chiat, so had to walk through the girls to get to the market.

But in all seriousness, I completely disagree with your characterization of Saigon. While you are certainly entitled to your opinion, my family (and many of my colleagues and their families) routinely would take weekend trips to Saigon from Singapore. There are some nice hotels, nice restaurants, good shopping, etc. It's simply wrong to suggest that all there is to do here is pick up hookers. Additionally, Saigon is one of the easier places to get in and out quickly, so the notion that you should only see it as part of a larger tour of the country is in my mind really bad advice. In fact, if you want to see the "rest" of Vietnam, my advice is to skip the 2 main cities and just get right on the road to other places., since that transit will really eat up lots of time!

Plus Jetstar has supercheap flights from SIN to SGN, so I'd skip KUL and spend a couple of days in SGN.