I thought I'd share this as we looked at the available third party Charting offerings with Xamarin Forms a couple of weeks ago (updated 24-Dec-2014)
The two client prerequisites for choosing a solution were:
• Two Finger Zoom
• Select a point on a chart to activate an event.
We looked at the following:
Telerik
http://www.telerik.com/xamarin-ui
Originally expensive and shipped with DevCraft ($1999) but last week (15th) they released, together with some major bug fixes, some new bundle options. The Forms 'bundle' (which will work on the Xamarin Platform) is $799 and it's 'just' a graph control at the moment but I believe there will be a couple of new controls added to the bundle in the next few months, including a new calendar control.
Syncfusion
http://www.syncfusion.com/products/xamarin
Two finger zoom isn't supported but the support guys have released a code snippet (please see attached) for activating events when touching points on a graph. The price is excellent value at $99 and the bundle offering includes Gauge, Graph, TreeMap, Excel, PDF & Word components! If you reference the specific platform DLLs, the component suite will also work with the Xamarin Platform.
Infragistics
http://www.infragistics.com/infragistics-xamarin-forms
The product range has yet to be released unfortunately so this isn’t an option.
Steema
http://www.steema.com/xamarinforms#a
Released on Friday 5th December
Originally the download link in the web page didn't work so we never got to look at it for our App.
http://steema.com/entry/233/TeeChart_for_Xamarin.Forms_new_release
DevExpress
https://www.devexpress.com/Products/Xamarin/
Currently not yet available (Rendering Soon...)
ComponentOne Xuni
http://www.componentone.com/Members/xuni.aspx
Currently not yet available (in Beta)
Conclusion
For our client project we went down the Telerik route, which at the moment seems to work well (thanks to the bug fixes last week) however for another project (which requires PDF, Excel output) we will be using the Syncfusion offering.
I hope this helps.
Steve