I've done 20+ rentals in different markets. I like to do a lot of homework. Find one. See if you can find same property listed for rent outside VRBO where it is almost always cheaper. Check out Google Earth view for better view of location, neighbors, etc. Look for reviews on multiple sites to ensure credibility paying careful attention to dates.
I've had only a couple minor issues.
1) St Croix: Property manager wasn't responding when we arrived. We ultimately entered a gate and found an unlocked door and let ourselves in. We tried more ph #'s, email contacts, etc. and somebody finally contacted us as said it was simply human error thank goodness.
2) Puerto Rico: House was not as nice or clean as pictures/reviews implied. We kept with rental and made the best of it.
3) St. Croix: Rented from property mgmt company. House sold between when we booked and when we were to stay. We booked in May for December. House sold in October. I didn't realize it was for sale. There was about 3 weeks where we didn't know if the new owner would honor our rent contract. Mgmt company was communicating, confident, but some risk. Was a bit stressful, but all was fine.
We will keep using this format as dislike hotel, resort, cruise ship vibe.