Debates between purists and progressives loom large in bluegrass, but this paradigm seems irrelevant to a sound this newfangled. The only traditional element these topflight pickers offer is instrumentation; the material is essentially highly adventurous pop songs. Nothing wrong with that, and a couple of them ("Me and Us," "Welcome Home") find a baroque lushness in the acoustic timbres and voices.
But most of the tracks are disappointing. Some compositional restraint would help—the Punch Brothers' earlier contrapuntal meanderings are diminished, but the general complexity still overwhelms the listener. The larger issue, however, is the strict string-band framework itself: while it's fine to eschew traditionalism for intricate pop, playing the latter without a note of piano, percussion or anything plugged in just sounds kind of gimmicky.