Serpwatch is a potential tool. I've been trying Serpwatch for a few months and here are some reviews:
Pros:
1/ The keyword position tracking is extremely accurate.
2/ UI is also great.
Cons:
1/ although the speed has improved significantly compared to before, I think it still needs further improvement.
2/ The report file is also a point that I am very dissatisfied with, instead of outputting all keywords in the format of 1 keyword column, 1 column location, 1 column of date, the tool outputs a confusing format.
Conclusion: I invested 5 codes in them, the tool is still new, I hope they will improve it more in the near future.