To all the people complaining about text formatting in Gmail, I strongly recommend Markdown Here:
https://github.com/adam-p/markdown-here. It lets you write emails as markdown and compile them to HTML in the email composition form. (I have mine bound to CTRL-ALT-Q). It works extremely well, I can easily store my emails in plain-text if I need to, I write emails in my text editor, and the Markdown utilities there make formatting much faster. It's great.
Chrome extension: https://chrome.google.com/webstore/detail/markdown-here/elif...
FF/Thunderbird extension: https://addons.mozilla.org/en-US/firefox/addon/markdown-here...
As for the UI complaints, I haven't hit too many of them, but those that I have have been very irritating. I don't use an email signature ATM, but I have run into the hard-to-change-sending-address quite a bit (I use +@gmail.com quite a bit), and didn't even know you could do it until just now. I only started using Gmail recently, so I can't say if it's worse, though it seems to be from what I've heard.