If you are strictly thinking of "good investment" in terms of money, then it is a "good investment" if you attend a public program (where tuition each semester is reasonable). Or if you have the money to attend private school programs without taking out huge loans.
Now, many people choose to go into this field because they are passionate about it, not just because of the dollar signs, and they gladly attend various private schools across the country. There is nothing wrong with attending private schools for OT -- USC, NYU, Columbia, etc have great programs. But if you are thinking strightly about your wallet, then you have a strong possibilty of graduating OT school with loans that will total more than your starting salary.
You really need to do your own research. Check out the AOTA website for schools near you, check out how much they cost, etc. Check out salaries online. OT salaries vary a lot depending on what setting you choose to work (pediatrics less, SNFs more). Think about what settings you could work in and how diligent you will be once you graduate and have to start paying off loans. There are people who can pull off the 80 hour work week and others who can't.
As with any other graduate program, make sure this is what you want to do before you commit. You can read plenty of unhappy ex-OT opinions on the indeed forums for occupational therapy. You don't want to commit to this career and realize you hate it 6 months in and wish you had just gone with pharmacy.