FWIW,
About even, but Ingram has been slightly better than Jaylen in preseason. He has the higher EFF rating (8.4 to 7.5). Comes down to better three point shooting and less turnovers.
Ingram: 8.1 points, 2.4 rebounds, 1.7 assists, 1.1 blocks, 0.7 steals, 0.3 turnovers with 41%/39%/54% shooting in 24mpg.
Brown: 10.7 points, 2.8 rebounds, 1.4 assists, 0.4 blocks, 1 steal, 1.7 turnovers, 42%/28%/59% in 23.3mpg
Ingram is 11 months younger. He's widely believed to have a high ceiling. While Jaylen wasn't widely believed to have a high ceiling, Boston clear thought otherwise. Hopefully they are right.