I’d guess from the 4.5%, you are in the USA? Just asking to check we share the same context here, no need to answer..

My subjetive experience in the USA (Seattle and NYC) is that you can get 4-5% with a steady job and 20% down for primary residence. Anything out of ordinary, like 2nd mortgage (since we are talking about real state as investment), the interest rate goes up (6-7% last time I applied for one).

Also, while the margin rates can be higher, there is more liquidity, smaller transaction costs, and much smaller fees.