@Etienne Dubois money is just one part of the business of real estate investing. Knowledge is arguably more important. Like the saying goes, “two men met on the street, one had money and the other had knowledge. The one with knowledge left with the money and the one with money left with knowledge.”
If you do have experience and knowledge, great. If not, With that sort of capital, it should be easy to find a partner who has knowledge and experience to invest with. However, I would still encourage you to learn some basics before you start. Even as a limited partner or “passive” investor, you need to be able to vet your investment decisions and understand the investment you are considering.
While I personally like the multi family space and am looking to grow into that sector, I do not believe it’s the end all-be all many people make it out to be. Yes it has many great attributes such as economies of scale, but it also has its own unique risks. Having all 100 units of you portfolio in one location presents a risk over spreading into different areas and markets. I own properties on the coast of Florida, I definitely like spreading them out geographically so one hurricane doesn’t wipe out my entire portfolio. Also, I like exposure to different markets. Real estate is local, and if another crash does come, I believe some markets will fair better than others. You could also split the money and invest $100k in five different multi family deals.
Ultimately, I don't think you can go wrong either way. The key is to do you homework and buy quality investments. Across the board, if you are looking for a true passive investment they tend to assimilate to similar returns. The typical multi family offerings touts a 9-10% cash on cash return and 15% IRR for limited partners. To do better in either multi or small multis or SFR you may need to take a more active role.