Learnings from the field...We are somewhere around our 6,000 mark of individual's OKR we have helped create.
The biggest lesson for us is the "one size does not fit all". OKRs touch every aspect of an individual's work-life, and as such there are multiple attributes that can be built into your OKR solution... The trick is to "begin with the end in mind, but not in hand" ( a loose quote from Steve Covey)...or "begin as you intend to end"...
If you miss incorporating any of the attributes that you will need later, your OKR system will either fail to launch, fail after launch... or require significant investment to recover it.
These are a collection of some of the attributes we have built into OKR solutions:
If you are interested, drop me an email and I'll send you a "Sizing Questionnaire" to help you determine which of these attributes your OKR solution requires.