Vinyl should go directly on concrete.The best hardwood floors in DFW are on plywood with tar paper between the subfloor and the floor. 

For example, we originally thought we would refinish 700+ sq ft of hardwood floors (some are in bad shape, but salvageable).  

This particular property is quite unique (Side by side duplex with 3 beds and 2 baths per side, hardwood floors, and completely updated...oh, and the last house on a cul de sac with almost no other multis in the entire town). 

I'm leaning with hardwood floors in the common areas, but carpet in the bedrooms. 

Spring for prefinished hardwood flooring.

For my own projects we have several rules that we follow. 1) hardwood flooring can be purchased in truckload sales for about $3.00 per SF.

I do not have any pictures of the properties yet but the owner stated that it has fairly new hardwood floors and the only thing that it needs is a new thermostat.

You can't beat the LVT for wear-and-tear, but if we ever sell, this neighborhood calls for hardwood.

I did use a contractor to help out with some of the major repairs (42 windows, brand new plumbing, new hardwood floors, and converting from radiators to central air) the rest I did myself so I got exposure to working with contractors and truly understanding what kind of work is involved and what some of the costs in a rehab might be and how to survey a property for needed repairs.

I learned that the property has hardwood refinished floors, new windows, a new roof, and new plumbing, even though I took a look inside the property and could have known that myself had it not been the first property I ever looked at inside and if I wasn't so focused on the age of the home itself..