I have created bar charts in salesforce using google chart api and they work fine. I have also created charts using reports and dash boards in salesforce. Displaying the charts in visualforce by using 'analytics:reportChart' is taking too long to load the chart. So I am using apex:iframe and dash board image url to display it in the visualforce page. So my question is, between google api charts and analytics:reportChart which is better ? and why analytics:reportChart takes so long to disaply ?. Is there a way to make it load fast ?
Not to discourage you but I gave up on VF charts after I couldn't get Visualforce pie chart to start at "12 o'clock" to work.
I guess you could experiment with caching of whole VF page? http://www.salesforce.com/us/developer/docs/pages/Content/pages_compref_page.htm,
Other than that - generic tips & hints for improving performance of Visualforce? Check the viewstate, fire up developer console, check browser's console for JS error messages, stop using Internet Explorer... ;)