This stuff was one of my first personal projects. I wrote several versions and demoed them around to maybe tens of people. Typical response was mild interest but no one wanted to use it. Too generic. In fact, it's more generic than Excel: Excel is packed with features that solve specific customer needs.

Dabble DB seems to have carved out a niche, but they executed exceptionally well: they have map integration, natural language parsing, all kinds of charts, all kinds of import/export formats... I'd recommend learning from them and copying them shamelessly (features, promotion, pricing, every aspect where you're not completely confident) instead of choosing a vertical.