Dear fellow monk!

That is a difficult question indeed, and I don't know if it can be answered without knowing the internals of your company etc.. So I can only give an impression how it was in the companies I worked for.

Generally, there seem to be four aspects:

1. Fun at work

This depends on the team you will work with, and of the kinds of tasks. I prefer design/implementation tasks over testing ... even if I know both can be equally challenging and creative. Working in test automatisation will be mostly working on concepts and implementing them ... but be aware that in case some of your companies projetcs get need/trouble you will be part of the testing-team faster than you can think ;-/
You need to decide for yourself if you'll like that.

2. Career options

In the companies I worked for, there were only few career-options for testers. Developers always have the choice of going the architecture, the requirements of the project-leader way. Tester have only the possibility of leading some testing group. On the other hand, when aiming for a career, some knowledge on testing and automatization is fine. But then prepare yourself to limit your testing-job to 1-2 years, and then change to some other job.

3. Money

If you change inside your company, there is probably no change in salary. In the company I work for, testers tend to earn less than other engineers ... however we tend to have "junior-engineers" as testers and "senior-engineers" as developers (as being part in the test-team is seen as a good way for people to learn about our products before developing them.).

4. Options outside your company

This is probably the "best" aspect of changing to the test-automatization-job. Automatization is a big buzzword, especially when combined with test ... because it promisses cheap and fast tests with high coverage. If you want to change to another job, being an expert in test-automatization is a huge plus (which will probably also have a positive influence on the money-aspect ;-). Be however warned that you will likely stick to the testing-part in future jobs ...

As said in the beginning, it highly depends on you and your situation what the best choice is. And of course my impressions are probably not representative and can be totally different in other companies.

Good luck with your decision!
Rata (interested in the opinion of the other monks)