I am a CPA and full time real estate investor. I have purchased over 400 single family homes and I purchase a multifamily per quarter/6 months. I can tell you that for a beginning investor a single family home is the way to go to start off with. There is a TON of learning that goes on when you first start owning real estate. Property management is the #1 thing that will make or break you with either SFHs or multifamily properties and you really really do not want bad management in a multifamily, it compounds the problems. If you are going to manage them yourself its very time intensive and for your first few you may want to go that route just because its really hard to find a good property manager. The mistakes you make on multifamily properties as a beginner are by nature larger and cost more money. Its great to learn this business doing a few smaller deals, understand the ins and outs, the tenant landlord laws, how to rehab your units for preventative maintenance, tenant headaches, etc.
The maintenance aspect is the primary thing to look out for. You have to make sure your roof, HVAC, furnace, appliances, plumbing, electrical, foundation, clean out piping to the street, etc are all taken care of and get a full inspection report. Those are the items that will kill you in this business if not taken care of up front, especially on a single family.
Hope this helps.
Matt