Re: Welcome move, code-wise
I am often hampered by not having access to code written by other scientists. If I want to test my shiny new algorithm against state-of-the-art efforts from others, it is a right pain to implement their methods from scratch.
I am generally in favour of sharing code, and try to make my code available as widely as possible. Doing so (hopefully) optimizes the overall outcome for the field.
However, there is a flip side to this coin, closely connected to the tragedy of the commons.
The currency of the academic-career world is recognition, which comes in two main flavours: publications and citations. By making (a good and useful) code freely available, I generally decrease the number of publications I will get: otherwise, researchers needing the code will have to collaborate and co-publish with me. It gets worse: When I do a good job writing and documenting the code, so that it can be installed, used, and modified without my help, I get fever collaborations still: why invite me, when the code works? Sometimes, it gets worse again: scientific codes are rarely written as a one-off: you typically expect to amortize the cost of writing the code over several related publications. But, if you make the code freely available, another group might scoop you by studying a system you had in mind and publishing the results before you do - so you end up doing the heavy lifting without accruing the benefit. Note that I am not talking in hypothetical: I've had all three scenarios playing out with my own codes.
In theory, I am supposed to be compensated by the increase in the number of citations to my work. In practice, the outcomes vary: some research groups will cite you every time they use your code. Others will cite you the first time they publish the results obtained with your code, then just cite their own first publication instead - even though they are still benefiting from your work. And then there are those who'd never cite you at all - even though it is clear that they must have used your code to get that they report.
For me personally, this is mostly a source of a minor irritation and sometimes of a major amusement at conferences: I have a permanent position which matches what I want exactly, and have no plans or desire to move elsewhere. I can therefore afford to be magnanimous about it. Unfortunately, my situation is more of an exception - and getting no publication/citation payback on a multi-year investment of developing a code can easily ruin the career of a junior researcher.