Anyone taken the new Alvia train route (Barcelona - Bilbao)?

We are spending a few nights in Barcelona in early September, then heading to Basque country. Wondering if the high-speed train is a good way to get across the country (as opposed to flying to Bilbao/Pamplona/Santander). Confortable? Vistas? Fast? We will be traveling with an 8 month old.

Thanks!