Have bought a number of pottery barn sofas. Love the PB Classic square, with soft pillows. Super comfortable. washable sofa covers and incredibly well built. My view though is that different people have different needs from sofas - for example, I find elderly people have more difficulty getting out of a soft lowish sofa, others prefer a firmer back and seat. So you really need to sit in the sofa you are planning on buying as that is something you cannot guess online. Most sofas are a hefty investment, so take your time so ensure comfort, as well as looks, are boxes that are ticked

As well as what ASV said, I always look for a really good warranty on sofas.