10 YR ARM rate is fixed for 10 years. It is bought by GSE’s.

For primary residence, it is usually available at the same rate whether you want interest only or a 30 YR amortization payment.
The rate will change in year 11 (Payment #121)

For investment property, you MUST take the amortized payment.

There is no prepayment penalty.

When the rate is the same, I recommend taking the I/O payment as your obligation, but pay the amortized payment if you wish.

One never knows when they might run into financial difficulty, and the obligation of the lower payment is a benefit.

Other lenders might offer different terms, but the prime lender rates require the above.

I am also seeing that GSE’s will no longer loan on non-owner condos, regardless of credit score or LTV (at the moment)

This is NOT a good thing with those that have condo rentals.