I've been using 6.1 for a few days now; for what it's worth this is my feedback. From my point of view there are two big problems: there is too much noise and not enough control over disabling RS features.
By noise I mean that whenever I type something RS is too much "in my face". Whenever I type something RS is screaming at me that something is not right. If the block of code is not accessible it colors it in a certain way, if there are refactoring suggestions I get the "action button" in the left side, if there's an error I see red everywhere, the IntelliSense is trying to guess what I want to do, and on and on...
I understand that these are meant to be helpful, but for somebody who knows what (s)he's doing it's not helpful, it's noise, it's annoying. I find myself thinking of how I should write something in order to please RS first; so it won't yell at me. You better declare that variable first or else you're seeing red. You better return something, anything really just make it shut up, before you even start thinking about thinking what the function should do. Guys, this is the death by a thousand cuts. There is too much noise; you can't focus when people yell around you, and you can't focus when your IDE is bugging you.
This was a problem with previous versions too, but it seems to be getting worse; which prompted me to write this post. All I would really need is the info bar next to the scrollbar. That much I can ignore; I could glance at it when I'm in "ok let's see if what I wrote is valid" mode. Everything else I would like to disable (underlines, action button, various colors, etc). Which brings me to my second point: you can't, or at least I wasn't able to figure it out.
I would also like to be able to disable per file-type integration. There is something like this for IntelliSense; would be nice to expand this to everything. It would be nice to, for example, tell RS to ignore Razor files completely. There are also various features that work better with other 3rd party plugins. I would like to keep using those plugins. If I can't disable something in RS then I have a choice: either uninstall those plugins or uninstall RS. There are a number of very cool RS features that we would like to keep using. Please don't make us choose...
Rant over :-)