QGIS Server limitations?

Update

New functionality has been added into QGIS Server and as of 2.2, QGIS Server can serve out data via WMS(version 1.3.0 and 1.1.1), WFS (version 1.0.0), WFS-T as well as WCS (version 1.0.0) standard.

The rest of the answer is still valid.

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I won't suggest the use of QGIS server in the production environment, since it has limited features.

The reasons are as follows:

• Very limited documentation help.

• No support for users or Groups.

• No inbuilt caching options.

• Slower performance than Geoserver (I don't have any stats or citation on this. I have just seen this in my personal testing)

I would suggest that you use a fully features GIS server like Geoserver in the production environment. You get things like a fully featured Admin Interface, WFS, Caching through GeoWeb Cache, several plugins, an OpenLayers Preview, and so on.

QGIS Server has some limitations but you can add Lizmap on top and get more functionalities.

• The documentation is good and often updated.
• It handles users/groups.
• Cache management
• Bing, Google, IGN, OSM base layers
• You can easily build html popup for getFeatureInfo calls.
• The Lizmap plugin is very handy and gives you a nice GUI.
• The Lizmap web client based on OpenLayers is the QGIS web client equivalent but it is nicer (my opinion) and you can easily modify it using theme. You get WFS controls to make crud operations.
• You can easily extend the openlayers 2 frontend binding to multiple events

I didn't test the performance but I never had problems.

Update 2017-01-17 : If you were not convinced by QGIS Server 2, QGIS Server 3 will be released around July 2017. It will be a complete rewrite. Give it a try.