I'll share my thoughts. I've done a lot of residential real estate deals including dozens of passive investments and have syndicated four apartment complexes.
REITS - These are more akin to stocks than real estate investing and do not come with the tax benefits. I do not invest in REITS
Passive Investing - I do lots of this. To date my annualized return has been north of 30%, so you can do quite well. However, you have to be very, very selective. You need to learn to read the PPMs and dissect what is in them. Without a hours-long conversation, here are things I consider.
1) I have never invested with anyone that charges an acquisition fee, and most syndicators charge an acquisition fee. If they get paid up-front, how hard will they work to make the deal profitable? I've seen as high as 4% acquisition fee, and anything 2% or over is too much.
2) I have never invested in a waterfall return. (Example 8% pref return, then 80/20 split until achieve 15% IRR, then 50/50) The main reason most syndicators offer a preferred return is because people that invest in mutual funds feel like they are guaranteed as high a return as they would get in the mutual fund. Typically waterfall returns will also come with a lot of fees to the syndicator because they are not going to work for free. (So, do you really have a PREFERRED return?) Also, this creates misalignment of interests as the deal unfolds.
3) Check the details of the operating agreement. Can the syndicator be removed if they are not performing? Are they required to publish financials or do they simple "intend" to publish financials? (There are passive investors in deals that haven't seen financials in years) Do the passive investors get to vote on anything or are they simply along for the ride.
4) Understand the business plan. How will they achieve the promised returns? Is that realistic? (I've seen deals where they say they are going to achieve $X in rent, but NOBODY in the submarket gets those kinds of rents.) How long is the hold time? What is the financing? Who is the property manager? Who is the asset manager?
I could go on, but that is a decent short list.