I work with a lot of time tracking data in my job (calculating the R&D tax credit). I like this tool a lot. It's simple, responsive, fast, and covers nearly all the relevant data points without any obfuscating clutter.
There are a couple items we look for that might be worth including in the CSV exports, depending on what kind of scale you want to plan for. Specifically:
1. Project name,
2. Project ID or number,
3. Employee name,
4. Employee ID or number,
5. Employee email,
6. Supervisor name,
7. Supervisor employee ID or number,
8. Supervisor email,
9. Task or activity code, and
10. Task or activity description.
It's important for us to be able to line up time tracking data to W2 data from a payroll system, which is frequently hosted separately with different data standards. So employee numbers (not SSNs obviously) really help when dealing with larger companies where a significant number of employee names may change (e.g. due to marriage) or may be formatted with slight variations (e.g. nicknames instead of full legal), or where the odds of a name collision are high. We also like to see departments, cost centers, legal entities, locations, lines of business, etc. where applicable, but we can usually layer those on from other data sources if we can join on a unique identifier, whether it's at the project, task, or employee level.
If I can get that data in a single CSV export for all employees at a company, I'm like 70% done with the calculation.
And while this sounds like an odd use case, pretty much any profitable company doing software development in the US should be claiming the credit (and actually in pretty much any developed country, because most have a credit that was modeled on the US's). Even smaller shops with only a handful of employees usually see substantial benefit. Having the data formatted like this up front reduces the costs of doing an R&D credit study and dramatically reduces the odds of an adverse adjustment in exam or audit. Especially when the employees have been diligent about recording their time and the associated activity/project/task data. It's also worth noting that this is one area of the tax code that does not seem likely to be affected by tax reform as both the Ryan and Trump plans propose to leave the credit as it is.
Edit: oh and I forgot because this doesn't relate to my work, but having an option for charge codes is nice. So something like [client ID].[project ID]. It will improve interoperability with third-party invoicing tools.