Entity Framework is mostly a problem for the same reasons that Hibernate can be a problem: it's a very powerful solution that can do a whole lot of work for you, but is overkill for the sorts of things it's good at, and can make it very difficult to track down problems when it creates them. It's just packaged in by default and very easy for someone to employ without having a full grasp of the ins and outs. At which point, you get n-way projections doing full table scans getting reified in memory so that somebody can fetch a single column from the first row. I wouldn't recommend EF, but I wouldn't recommend NHibernate, either, and for a lot of the same reasons.

I don't know if I'd believe that Eclipse is better than Visual Studio. Certainly wasn't my experience when I last touched Eclipse (a decade ago: hopefully Eclipse has improved by leaps and bounds, because VS 2015 is a lot better than VS 2005!). This seems like a thing where details are probably necessary to contextualize the comparison. (My own experience has been that the tooling, at least on Windows, is one of the nicer things about programming in .NET.)