I've never used Sequel Pro, but I've used plenty of other RDBMS GUIs. What's so special about Sequel Pro? It certainly doesn't look like anything to write home about (compared to say the MS SQL tools).
1) Every GUI function results in a SQL log entry so you can learn/improve your SQL if you're not a guru.
2) You can give this to an analyst (whose db user is restricted appropriately) and have them be productive in adding and updating data.
3) Any view can be exported to CSV, so the analyst can use what they know (ie, Excel) to do things you might not care about but are important (ie, pivot tables, etc).
4) It's free.
Compared to every other RDBMS GUI I've used:
It crashes very infrequently. It doesn't randomly slow down whenever I click on something. The settings page is relatively straightforward. There aren't fifteen different windows with different functions. The UI makes sense and is also very straightforward.
So, I was rescuing an MS Access application that imperfectly synched from a MySQL instance powering the Rails app from which it got data, that had been exported to MS SQL that was running (surprisingly well) inside a Windows XP VM I was accessing via Remote Desktop Connection.
So: I have no idea. I totally forget. It was some really-complicated-looking MS tool that allowed me to look at the table row by row and run some queries :). The guy I was working for set it up; my excuse is I stopped using windows back in 2004.