Xcode is extremely slow even for operations that perform no IO at all, like code completion, or printing a variable in the debugger. (Seriously, I've had it take ten seconds to perform 'print foo', and not as a one-off thing either.)

Xcode chokes on large text files as well. A large file that VC++ can dislay and edit easily will be glacial to navigate and edit in Xcode.

Yeah, I've seen that, too. My experience has been that it takes several seconds to open the file or to switch back to it from another file, but once it's opened, I don't find editing it to be slow.

Yeah, the debugger one I don't get at all. I don't see the same problems in lldb on the command-line. In the past (when it was using gdb) I was told it was due to the data formatters. I would turn them off and the problem would go away, but I no longer see a way to turn them off.