Stocks with aggressive buyback programs have little or nothing to show for the money they spent.
Their growth rate (RR, or Reinvest Return) is a percentage point better than average but this likely is entirely attributable to the deductions from book value due to buying back shares above book value (its called 'decimating the denominator' and is good for executive compensation bonuses).
The result of the higher return and lower P/E is a shorter Payback (PB) for the Buyback stocks, i.e.8.0 vs 8.5 years. These stocks are cheaper!
It is interested to note that the median target Payback (NM) for all stocks is 103% of the S&P 500's while the Buyback stocks' target is only 95% which suggests lower long term valuations.