I'm guessing it would be about 50% cheaper and with regular maintenance it should last you 20+ years.

However, it’s crucial to ensure that the HVAC system is adequate for the space to avoid high energy costs.Flooring: The hardwood flooring adds a high-end touch but will require regular maintenance to prevent scratches and wear.

You still have a young loan so  let the amortization run its course and set your regular income aside for the next opportunity/project that you want to explore.  

To really know the result, I'd need to be advertising two identical properties -- one with a premium listing and another with a regular listing.Does anyone have experience that clearly shows a result from using a premium listing?

If you have that much business you are sending agents i'd get licensed and then just place your license with a referral agency so you don't have to pay the regular dues and can still collect a referral fee

I keep in reasonable regular contact with guests before their stay but I will not provide access or location information earlier than an hour or two before their stay, as I have had people show up before guests have left and before cleaners have finished.

However, if you don't mind taking on that risk, you can also run numbers for condo units so that they still work as regular rentals.

Of course, responsible landlords budget for regular maintenance and repairs.

These are heavy-hitter, regular buyers.

I would call them first, let them know you are sending it and then send it via email and regular mail.