Hi there! I would say if Gordon Hall feels like your only option, try not to worry too much, opinions on student accommodation tends to fluctuate person to person. Whilst I have not lived in Gordon Hall myself, the Cardiff accommodation website is quite accurate in how it is. You could have a go at looking at reviews online on other sites as well - websites such as StudentCrowd helps me often to make a decision.
If you decided Gordon Hall wasn't for you, there are many other student accommodation close to the engineering building. In terms of university-owned accommodation, Senghennydd Court/Hall is still really only an 8min walk.
There are also many private halls based near city center, but also a very short walk to the engineering building. Accommodation such as Adam Street Gardens, West Wing, Eclipse, The Neighborhood, etc. These halls are more luxurious, but they tend to be a lot more expensive than university halls.
Hope thats helped,
~ Fatiha, Cardiff Student Rep