the villas and attached homes sell extremely well in the greater St Louis area and have as great of resale value and appreciation as the single family homes do. They are very popular in the greater St Louis area.
Many of the buyers I work with have busy lives and don't like to bother with yard work, or they travel and want to know that the yard will be kept up while they are gone. I also see buyers who don't like to shovel their own driveway and sidewalk when it snows. For these and other reasons, they opt for the villas and attached homes. Today's villas and attached homes have a great deal of insulation between the homes which prevent noise from passing from one unit to another. In addition, many are designed so that the front doors are not in direct view of each other, so walking in and out you never see your neighbors' homes.
The real pros and cons, however are more along the lines of the monthly fees. The attached homes and villas typically have an association fee that covers the maintenance of the common areas, shoveling the snow, mowing the grass, and insurance on the exterior of the homes and common elements. This means that each month the home owner has to pay the association fee, along with his mortgage. If the complex is well run, they will have adequate reserves to cover big ticket items in the future without the need to have an assessment. If they aren't well managed, however, that can be an issue. That is why, in writing a contract, the Realtor will attach special riders asking to see the condo's financial paperwork so the buyer can review it before purchasing. When a complex is well run, the monthly fees will equal the amount that a responsible home owner would expect to pay if they were paying the insurance on the exterior and the amount that they would be putting aside to pay their annual taxes and for future big ticket items (like a new roof or siding).
The other side of the coin is personal preference. I have had some sellers who sold their villas and returned to single family homes because they loved to garden and do yard work.