Pros:
-Notts has a stronger rep in a broader sense to employers. E.g. law, IB, consulting. So, if you decided you didn't want to pursue a career in engineering, we have more career fairs with the aforementioned employers.
-Campus investment is massive and growing - e.g. the David Ross Sports Village, Engineering Library (George Green) and continued expansion. It's in the top 3 in terms of campus investment and it makes everything pleasant. Engineers have a few new facilities.
-Study abroad, if that interests you, is great here as it's a U21 member. For instance, I'm studying at the National University of Singapore next year as an exchange student. Not sure how comparable this is to Soton.
-SU is always ranked within the top 10 and recently had renovations. There are lots of extracurricular activities here, from languages, to skills building, to actual societies to get involved with.
-I often wonder how anyone can leave here without a grad job lined up, and my conclusion is that they chose not to do anything productive alongside their degree. There are endless opportunities, and the only way you'd leave without interviews for a job you want is if you neglected everything around you.
Cons:
-Really large - contentious but it can be daunting to some people.
-Cliquey - not too noticeable, but due to the Asia campuses of Notts, we have a lot of Chinese/east Asian students who stick together and don't seem to like speaking English.
-Hard - a friend of mine studies engineering and is told regularly that they try to make the course the most rigorous in the UK. I can't personally comment on this, but you'll study some things that most others don't until second year at different universities. No idea compared to Soton. Although, I think this is a pro if you don't mind hard work since you leave with high skills.
Honestly, there aren't many cons of Notts, and the ones I listed are subjective. The campus, academic atmosphere and career opportunities are superb.
If you have any specific questions, feel free to ask.