I've lived in the slopes and have no complaints. Some areas come with beautiful views and some of the houses in that area can be a real steal. I completely expect that area to continue to rise in property value over the next few years because of continually rising interest from (shitty) rental companies buying up and "renovating" houses. As an investment, slopes might be the better move. That being said, I have a soft spot for any neighborhoods between the rivers. It's my personal favorite part of the city. I think I'd prefer Greenfield despite never having lived there.

I hope you don't mind hills with either one haha