Watch your indent patterns:

```javascript
var id = req.params.id,
  code = 200,
  ..;
```

Here again, just about all these variables are unneeded.  A better approach for this pattern is something like:

```javascript
exports.get = function( req, res ) {
  var id = req.params.id;
  UserHandle.findById( id, function( err, user ) {
    if ( err || !user.length ) {
      res.json( { error: err || "User not found for ID: " + id }, 500 );
      return;
    }
    res.json( { error: null, data: user[ 0 ] }, 200 );
  });
};
```

I think you're using variables so you can have single exit points, but that's not necessary--it's fine to return early.  Also, I switched to json above, is that what you should do here vs. `res.send`?