I've used it on and off since it was in beta, almost a year. (I should have added a disclaimer that the developer is a friend.)

It's good if you want to set goals for N pomodoros on task area A, M pomos on project B, etc. and then work predominantly in pomo-mode and track your progress on your goals. If you don't use the timer mode, hand-entering time spent probably will get tedious quickly. It's designed to help particularly with time-boxing (i.e. when you're budgeting out a limited amount of time across projects), though I don't use it that way.

I think it's pleasant to use in day-to-day use, decent UI.

Cons: I find that I have a hard time doing my planning (time allocation) on a mobile device screen. I want to do it on a big screen where I can see everything, or on paper. I'm not good at regularly triaging the list and adjusting it, so the goals tend to grow stale and I start ignoring them a bit.