real case: sp500 or rental house, which one better?

I have a friend, who bought a house in 2005, and also bought some sp500 in 2006.  The house was 500K and was rent out for 2000 a month, now it worth 450K and rent for 2400 a month.  The sp500 he bought was at all time high at 1400 in 2007, now it is 2500.  both rental house and sp500 was bought at the peak.  Now more than 10 years, which one has the better return?  I can't figure it out.