Not enough responses = priced too high (assuming your marketing is dialed in).  10 showings w/out an application = something is wrong with the unit (cosmetically: not clean, didn't replace blinds, etc = clean it up more) OR (functionally: unit has issue that comparable units in the neighborhood don't have - street noise, weird layout, etc = lower price to combat issue).  

Our nightmare tenant also resulted in other tenant complaints, cops being called for noise, parking crazy in the parking lot taking up two spaces, destroyed carpets where they let cigarettes fall and burn on the carpet (and smoking wasn't allowed), her baby daddy moved in almost immediately - it can result in lots of time dealing with complaints and problems and I almost lost good tenants, too, who I had to assure I was getting rid of the nightmare tenants.  

Has anyone had issues with too much foot traffic noise from tenants who live in apartments above.Our tenants are not being overly loud but they have several kids and just the normal life with toddlers can create significant foot traffic noise for our other tenants.

So, I took them if they proved they were full-time students, although, I tried to avoid them just because they cause noise and damage.That was probably more info than you wanted lol. 

Downstairs room tenant was out living in hotel for last 4-5 days as noise of these machines is too much. 

But IMO if 40% of rent was not being paid widely there would be a lot more noise 

The reason is because if you have an apartment building with multiple tenants, it's easier or more accepted that when you're a tenant in that building, you expect to have the noises that are normal for living in a multi-family building and are prepared to kind of blend in - it's more anonymous.In a duplex, it's more like having to get along with a roommate that you can't kick out.  

The place smelled of pizza & the noise & heat from below was terrible. 

Ive been doing my dueldillengence and trying to studying up on market trends, but everyone is saying different things and it hard to block out the noise.

I don't know, I look at these places and don't get me wrong they're nice, but 300K seems just too much for the square footage, hence I can hear the bubbling noise ;)