Dreamweaver is a web development tool built for designing pages with HTML and CSS using template pages, text editing, and a what you see is what you get editor.
This program is a must-have if you work in any HTML-based programs. It's convenient for HTML emails and tweaking code used in Wordpress. It's also greta for editing older PHP sites I manage for clients, I do not use it for new websites anymore as I feel other solutions are more suitable for my clients.
I would recommend Vim in any scenario where text files have to be viewed, created, or edited on GNU/Linux computers. Regardless if you need to quickly change a few things in a configuration file, or you need to write up a full document, Vim is great. I wouldn't use Vim to view, edit, or create anything that requires "rich-text". In other words, if you need to format the text (bolding, font colours, word-art, etc), then Vim isn't the tool to use.
Adobe Dreamweaver is very useable and easy to navigate. It's features are fantastic and documentation on how to use the software is very detailed. If you can't find how to do something, the help file is fantastic and works great!
I don't consider the steep learning curve to be a hinderance on the overall usability. I would rate this a ten, but to be honest a lot of people do get hung up at the beginning and just abandon it. However, for people who have made the moderate effort to get over the hump, nothing can be more usable.
There is no commercial support for Vim. Thus, it will not get a mark beyond 5. However, community support is very good. You can easily find solutions for most of the problems in the community.
Google Web Designer is what I used to use but Dreamweaver was better. Google did not offer the functionality I needed. Google was also messy and had limited design options. Google seems better for creating animated banners or animated photos, but not for designing a full website or designing HTML.
Vim's keybindings are a lot more complex than Notepad++. With that, comes a whole bunch of capability that Notepad++ just can't match. Emacs is comparable, in terms of capabilities--because Vim is built into so many unix systems, I chose to learn it instead of Emacs. Knowing both probably isn't a bad idea, but there's enough to learn in either camp to keep you busy