I do a know a few CA investors that buy all OOS (Texas is still a popular place to invest) but the majority of investors I've talked to at meet ups and friends and family still own in CA.

A popular formula is to analyze the "70% Rule" (70% of ARV minus repairs) for a flip, while focusing on cash-on-cash return for holding.

Investing in multifamily properties in Philadelphia is popular due to the city's steady population growth, job opportunities, relatively affordable property values, and solid rental demandPhiladelphia’s multifamily market offers a range of opportunities, from high-end neighborhoods to up-and-coming areas with great cash flow potential.

Airbnb increased the popularity of STRs, but did not introduce STRs (VRBO started in 1995).  

The condo’s potential for consistent income on platforms like Airbnb, coupled with the area's growing popularity, made it a strategic addition to my investment portfolio.

We have seen Brampton become a popular city for duplex properties as many of them have basement with separate entrances.

Charlotte is a tough market for investors at the moment as we have had a considerable rise in the average price of housing as it has become more popular here. 

On another G.R. house, I have used a program through the city "Get the Lead Out", a somewhat more popular program for some time here. 

I am Texas based so may answers will skew more towards my region but I would leave to hear what are some other areas you may be paying attention to that isn't as popular as some of the main stays (Smokies, Joshua Tree, etc)Mine right now are 1.

From there, there still may be operational issues such as the  property being too seasonal and having a bad weather season or the market simply losing popularity.