Looks great, and I like that there is a lot of overlap with Grist: https://news.ycombinator.com/item?id=25257521, https://www.getgrist.com (of which I am a founder). The differences are interesting: rows.com seems more focused on external integrations; Grist has API but is more focused on powerful formulas and layouts for working within the data.

I imagine the overlap will only increase. I take it as confirmation that these are good ideas to pursue.