I would prefer to buy property any time. People will always need housing. So while the price of the property is pure speculation, rent is a nice steady source of income.
If I decide the housing market isn't for me or I need to raise cash quickly, I could be forced to wait anywhere from 8 weeks to 18 months, or longer to get any of my investment back (even longer if I don't want to lose money through desperation to sell).
If I need to raise money from stocks or index funds I can get market value for those investments instantly during business hours.