I'm slightly biased on this but have a look in to them. Start with the Backstreet Symphony album, their first album. It's probably their best and one which was hard to live up to. Almost like coming out with a Hysteria or Slippery When Wet as your debut. The follow up albums are a treat and didn't disappoint. The songs have a great depth to them, especially in the later albums. Danny has one of the best voices, such a range. Very soulful. I also shared Danny and Luke's (lead guitarist and main songwriter) version of "I can't stand the rain"