Our Blue Angels framework shows that the S&P 500 was back in record high territory last week as S&P 500 forward earnings rose to yet another record high (chart). Meanwhile, the S&P 500's forward P/E has been relatively steady just above 20.0 in recent weeks.
The S&P 500's forward P/E with and without the MegaCap-8 stocks is currently 20.6 and 18.2 (chart). The MegaCap-8 is currently trading at a forward P/E of 28.3.
The S&P 400 MidCaps and S&P 600 SmallCaps are currently trading at forward P/Es of 15.0 and 14.2 (chart). So they seem relatively cheap.