MHPs or self storage business? which is better for a newbie

For a new guy trying to jump in and get some good solid cash flow what would be a better option for me?

I own the place I live in and a condo-rental that is cash flowing $600/month.

I have a full time job. After my expenses I save $2500/month.

I want to make more cash flow so am debating between MHPs or self storage units.

I think both would be great… but what would be a better option to start off with to get at least an extra $1500 a month. I have about 50k to invest as a down payment.