What considerations are important in choosing between the two styles below? Interpretability, maintainability, speed, other?

purrr_happy.R

library(purrr)
library(magrittr)
library(microbenchmark)

y_test <- sample(0:9, 2000, replace = TRUE)
pred1 <- sample(0:9, 2000, replace= TRUE)
pred2 <- sample(0:9, 2000, replace= TRUE)
preds <- list(pred1, pred2)

# want to apply the following to preds
# sum(diag(table(y_test, pred)))/length(y_test)

#
# this 
#
preds %>%
  map(table, y_test) %>%
  map(diag) %>%
  map(sum) %>%
  map_dbl(divide_by, length(y_test)

#
# or this
#
preds %>% 
  map_dbl(~{sum(diag(table(y_test, .x)))/length(y_test)})

microbenchmark(
  setup = function() {
    y_test <- sample(0:9999, 1e6, replace = TRUE)
    pred1 <- sample(0:9999, 1e6, replace= TRUE)
    pred2 <- sample(0:9999, 1e6, replace= TRUE)
    preds <- list(pred1, pred2)
  },
  # This
  readable = function() {
    preds %>%
      map(table, y_test) %>%
      map(diag) %>%
      map(sum) %>%
      map_dbl(divide_by, length(y_test))
  },
  # Or This
  compact = function() {
    preds %>% 
      map_dbl(~{sum(diag(table(y_test, .x)))/length(y_test)})
  },
  base = function() {
    preds_table <- lapply(preds, table, y_test)
    preds_diag  <- lapply(preds_table, diag)
    preds_sum   <- sapply(preds_diag, sum)
    
    preds_sum / length(y_test)
  },
  times = 1e6
)