I used Flipper Force for a while and liked it as well, but the accounting features aren't good enough so it wasnt worth the money for me just to use the project management portion when ClickUp does it well. 

I really depends on the specific property and location.Get a good enough deal and you can cash flow. 

The Go Daddy vacation rental template was good enough for me and super easy.

The short answer is yes in my opinion.As you say the great properties in great areas are always going to do well.The "Airbnb" type properties (Ones not good enough to do well on Vrbo) are going to struggle unless they have something going for them like being close to someplace like a hospital, university or are very walkable to something interesting. 

It eats up too much of my and my partner's time.Our rehabs have been good enough to generate a big bump in rents and cash flow, beyond our projections.That said, we have had to sink a lot of our own time & labor into the rehabs, so it is definitely an intensive investment.

Would that be good enough reason to deny a tour? 

The deal has to be good enough with your assignment fee included, otherwise nobody will want it. 

Or a loan from someone to make their bank account look good enough to qualify for a rental (weird but possible).

Are there any free tools that are good enough to help with market / potential investment analysis or would you recommend paying for a tool? 

It sounds like these were good tenants and the $1,000 charge is questionable (could fall under normal wear and tear and nobody should expect a tenant to maintain garden beds perfectly, that one is too subjective to prove they didn’t go a good enough job IMO).