Hue, you were very interesting but we kind of had a love/hate relationship with you. There were aspects of your architecture that we loved but you were incredibly hot and just not what we expected. Maybe it was the location we were staying, even though we thought it was quite central but we felt that there just wasn't much of a touristy vibe there.
We only spent a short time in Hue and I would recommend only staying two, maybe three nights to explore the 19th century Citadel & the Imperial City. We didn't get a chance to go into the Imperial City as Dylan was quite sick and trying to walk around in 40+ degree heat isn't ideal. The other reason was that it was hard to find the exact price of how much entrance was as a lot of the blogs we had read say that depending on who you get the ticket from, the price sometimes varies. The most reliable we found said that it was around 150,000VND, so roughly $10/$11 AUD.
If you were doing a trip through Vietnam, it is probably a good spot for a short layover but I wouldn't recommend staying a long time.