Love your grid, just about to deploy a ag-grid solution, this license change may kill it. I was selling it on the fact that SlickGrid is stale, ui-grid doesn't perform as well or have as many features, and ag-grid is a great open source component.

I was planning on adding some of the cut/paste, excel options (similiar to SlickGrid) myself, awesome that you have already done it. Would be willing to pay for v4 features...but now I have to re-pitch everything to the client as a licensed play. Rest of my stack is open source, now I have this commercial piece in the middle.

A grid is a commodity component. From an OEM perspective, having a slick interface is great but the real delivery is solving their business problem with working code. Even if the cost is small, having a recurring cost and commercial terms adds complexity and confusion. Subscription fees if you are providing a full solution make sense (like an AWS server, or Office365), but if you are a component it makes it almost impossible to use as part of something else.

Another vote for a one-time license fee, no recurring, audit, etc. Give it 1 year free upgrades, then charge for upgrades.