@DarkoL: in VS '15' we are focusing a lot on performance/reliability/install time, with some of the performance improvements available in VS2015 Update 3. If you are working in a large solution, these suggestions may help improve your performance as well.
@Siderite: if you're curious, you can see the code in ObjectFormatter in the roslyn codebase. Carrying it over into the expression evaluators for the debugger is on our backlog. You can follow that work/discussion here (note the issues referenced at the bottom of the issue as well).