diff --git a/IPython/core/application.py b/IPython/core/application.py
index cc1ff9d..9a4bbe3 100644
--- a/IPython/core/application.py
+++ b/IPython/core/application.py
@@ -272,10 +272,7 @@ class BaseIPythonApplication(Application):
         if self.profile_dir is not None:
             # already ran
             return
-        try:
-            # location explicitly specified:
-            location = self.config.ProfileDir.location
-        except AttributeError:
+        if 'ProfileDir.location' not in self.config:
             # location not specified, find by profile name
             try:
                 p = ProfileDir.find_profile_dir_by_name(self.ipython_dir, self.profile, self.config)
@@ -295,6 +292,7 @@ class BaseIPythonApplication(Application):
             else:
                 self.log.info("Using existing profile dir: %r"%p.location)
         else:
+            location = self.config.ProfileDir.location
             # location is fully specified
             try:
                 p = ProfileDir.find_profile_dir(location, self.config)
diff --git a/IPython/parallel/apps/ipcontrollerapp.py b/IPython/parallel/apps/ipcontrollerapp.py
index a4b879d..275c406 100755
--- a/IPython/parallel/apps/ipcontrollerapp.py
+++ b/IPython/parallel/apps/ipcontrollerapp.py
@@ -399,9 +399,9 @@ class IPControllerApp(BaseParallelApplication):
         q.connect_mon(monitor_url)
         q.daemon=True
         children.append(q)
-        try:
+        if 'TaskScheduler.scheme_name' in self.config:
             scheme = self.config.TaskScheduler.scheme_name
-        except AttributeError:
+        else:
             scheme = TaskScheduler.scheme_name.get_default_value()
         # Task Queue (in a Process)
         if scheme == 'pure':
diff --git a/IPython/parallel/apps/ipengineapp.py b/IPython/parallel/apps/ipengineapp.py
index 93a012c..4bc5719 100755
--- a/IPython/parallel/apps/ipengineapp.py
+++ b/IPython/parallel/apps/ipengineapp.py
@@ -211,14 +211,9 @@ class IPEngineApp(BaseParallelApplication):
         
         # allow hand-override of location for disambiguation
         # and ssh-server
-        try:
-            config.EngineFactory.location
-        except AttributeError:
+        if 'EngineFactory.location' not in config:
             config.EngineFactory.location = d['location']
-        
-        try:
-            config.EngineFactory.sshserver
-        except AttributeError:
+        if 'EngineFactory.sshserver' not in config:
             config.EngineFactory.sshserver = d.get('ssh')
         
         location = config.EngineFactory.location
@@ -313,21 +308,17 @@ class IPEngineApp(BaseParallelApplication):
             self.log.fatal("Fatal: url file never arrived: %s", self.url_file)
             self.exit(1)
         
+        exec_lines = []
+        for app in ('IPKernelApp', 'InteractiveShellApp'):
+            if '%s.exec_lines' in config:
+                exec_lines = config.IPKernelApp.exec_lines = config[app].exec_lines
+                break
         
-        try:
-            exec_lines = config.IPKernelApp.exec_lines
-        except AttributeError:
-            try:
-                exec_lines = config.InteractiveShellApp.exec_lines
-            except AttributeError:
-                exec_lines = config.IPKernelApp.exec_lines = []
-        try:
-            exec_files = config.IPKernelApp.exec_files
-        except AttributeError:
-            try:
-                exec_files = config.InteractiveShellApp.exec_files
-            except AttributeError:
-                exec_files = config.IPKernelApp.exec_files = []
+        exec_files = []
+        for app in ('IPKernelApp', 'InteractiveShellApp'):
+            if '%s.exec_files' in config:
+                exec_files = config.IPKernelApp.exec_files = config[app].exec_files
+                break
         
         if self.startup_script:
             exec_files.append(self.startup_script)
diff --git a/IPython/parallel/controller/hub.py b/IPython/parallel/controller/hub.py
index e049fc9..6de8772 100644
--- a/IPython/parallel/controller/hub.py
+++ b/IPython/parallel/controller/hub.py
@@ -255,10 +255,9 @@ class HubFactory(RegistrationFactory):
 
         ctx = self.context
         loop = self.loop
-
-        try:
+        if 'TaskScheduler.scheme_name' in self.config:
             scheme = self.config.TaskScheduler.scheme_name
-        except AttributeError:
+        else:
             from .scheduler import TaskScheduler
             scheme = TaskScheduler.scheme_name.get_default_value()
         
diff --git a/IPython/qt/console/qtconsoleapp.py b/IPython/qt/console/qtconsoleapp.py
index 3ef7fa1..1475938 100644
--- a/IPython/qt/console/qtconsoleapp.py
+++ b/IPython/qt/console/qtconsoleapp.py
@@ -281,18 +281,10 @@ class IPythonQtConsoleApp(BaseIPythonApplication, IPythonConsoleApp):
         # are removed from the backend.
 
         # parse the colors arg down to current known labels
-        try:
-            colors = self.config.ZMQInteractiveShell.colors
-        except AttributeError:
-            colors = None
-        try:
-            style = self.config.IPythonWidget.syntax_style
-        except AttributeError:
-            style = None
-        try:
-            sheet = self.config.IPythonWidget.style_sheet
-        except AttributeError:
-            sheet = None
+        cfg = self.config
+        colors = cfg.ZMQInteractiveShell.colors if 'ZMQInteractiveShell.colors' in cfg else None
+        style = cfg.IPythonWidget.syntax_style if 'IPythonWidget.syntax_style' in cfg else None
+        sheet = cfg.IPythonWidget.style_sheet if 'IPythonWidget.style_sheet' in cfg else None
 
         # find the value for colors:
         if colors: