Topic: Automation in a web environment

I'm working on a web based financial application that is somewhat dynamic in nature. Our shop uses AstraQuick Test to test basic functionality as well as links, labels, contents in drop down boxes, etc..

I've found Astra to be pretty unstable as an application/tool. I also need more capabilties (ex. a way to email myself when the script fails). Does anyone experienced with different tools for web automation know if other tools such as WinRunner or Silk would give me more stability and greater capabilities for my situation?