Tools to monitor Oracle Database Performance on Standard Edition Here is what I am looking for:


Works on Standard Edition i.e. No Diagnostic Pack.  
Provides both current and historical performance data.
Good visuals for easy spotting of trends and presentation to management.


If you have used the tool, I would be interested in pros and cons you have discovered.  I can come up with a list, but the insight of actually having used the tool is worth far more.
Note: I've never used this, so please edit this answer if you have.

Lab128






  Lab128 provides additional savings by implementing ASH functions and
  not requiring the purchase of ODP.


Pros:


Response Time Analysis
RAC support
Agentless
Only $299 for a named user connecting to two instances and only $499 for a named user connecting to an unlimited number of instances.


Cons:


Interface isn't very polished.
Lack of alerts.
One writer/maintainer.
No web interface.
Not server based.