ODK offers a powerful and highly flexible form development platform that is incredibly easy to use. I continue to be amazed at how quickly custom data collection forms can be deployed to employees in remote locations and how well everything works. My favourite features are 1) entities which allow for data records to be examined, updated, and built upon across workflows, and 2) the automatic deployment of new form versions within 15 minutes of updates or simply upon hitting a refresh in ODK Collect. I also find ODK Forum and ODK Docs extremely helpful - I am not an IT professional yet I was able to independently set up ODK Central on a server with these resources within a day.

ODK Central has a very simple and well laid out interface making for some really delightful navigation. New users will be especially thankful for this and the inherent lack of a learning curve. All the same, for power users who would like to look under the hood, the documentation and forum will be more than sufficient. The team is especially open to hearing ideas from users on things they would like added and/or modified. They welcome the conversation and help better understand how everything ties together and even the thought that goes into some of their design choices. The customer support and turnaround time on issues is a lifesaver. One other thing that comes in handy is ODK's ability to integrate with other data analysis/manipulation tools as well as the API to access, manipulate and manage your data as you see fit.

XLForms can be created before subscription. Fast response from the support. I found the available resource materials very useful to learn how to create Forms and upload them to ODK. The created Forms can be used as templates for other similar surveys later on.