The decorative Gothic-styled spire dominates the city's skyline, which has irked some people such as noted architectural critic Nikolaus Pevsner who accuses the church of being "a demonstrative proof of how intensely the Gothicists hated the Georgians of Bath."

Christopher Martin takes a more measured view in his work on English Catholic churches, commenting "the stately interior is a good reflection of mid-Victorian taste", and remarking on the colourful polished marble, the exquisite screen, the blazing and triumphant white tabernacle, the delicate communion rails, a series of references to St John, and the chapels, each with something to admire.

For this reason, they are often quoted as being the second best Roman Catholic architects of their day, for their success in picking up commissions Pugin had passed over.

The baptistery, a shrine containing the relics of Saint Justina of Padua, was designed by Edward Joseph Hansom, his son, in 1871.

Genuine C15 vestments are in use at St. John's.The church was put up by the Benedictines based at Downside Abbey, which accounts for the substantial ancillary buildings intended to accommodate a small community of priests.

The building was bombed in 1942: four people died and the south aisle was destroyed, but subsequently rebuilt in a similar Gothic style.