A320 layovers are in Berlin, Stuttgart, Vienna, Rome, Venice, Milan, Budapest, Sofia, Zurich, Moscow, Entebbe, Nairobi, Dar Es Salaam, Seychelles, Maldives, Colombo, Trivandrum, Cochin, Calicut, Hyderabad, Calcutta and Katmandu. Probably forgot some.
Most layovers are around 24h, some can be 18h (Colombo) and the occasional 30-48h (Berlin, Milan, Rome).
Hotels range from very nice like Budapest, Hyderabad and Calcutta to bad like Calicut. Actually, to call the Taj in Calicut "bad" would be an insult to bad hotels.