Good question - and it depends on what you're looking to get out of it.
I did a handful of single family properties before going into multifamily. I got to a point where lenders wouldn't give me another loan and I didn't know enough to be able to push past that. So, naturally, when I made the decision to scale and take my business to the next level, I decided to get into bigger and bigger multifamily properties. What I decided to do was learn to syndicate even larger multifamily deals, and I'm now partner on over $50 million in apartments...
Obviously, my situation and path are different than you and I'm not recommending that you do as I did. I will share WHY I went that path and maybe that'll help...
First of all, I wanted real estate to replace my day job. I looked at how fast I could save up down payments on single family properties and projected that it would take over 10 years to build a SF portfolio big enough for me to exit my W2. There's also the difficulty getting loans once your portfolio gets to a certain size. For me, 10 years was too long and the lending aspect seemed too difficult to keep going in the SF space (of course, there are ways past those to blocks, but I didn't know that at the time).
Buying smaller multifamily became attractive because I could make one purchase and own many units, but I ran into a similar situation as before in that it would take me a few years to save up the down payment for another and I was afraid that it would take a long time to snowball.
Finally, I landed on the syndication model where you find larger properties and also people that want to invest in real estate and bring the two together. I settled here because I wasn't limited by my own bank account... I could keep buying larger and larger properties as fast as I could find investors - and best part is, I could also find partners to share the load.
Bottom line, look at WHERE you want to be in 5 years and pick the path that gets you there. I wanted to go big quickly, so syndication was my choice. The SF or small multifamily models will also help you grow your wealth and passive income.