It's all speculations at that point but if the only reason to go to BitBucket is price then Atlassian is creating a community of poor/cheap people. The scenario for up-sell seems quite compromised in that regard.

Another thing is that if you're using open source products then they're likely on github. I agree that both platforms have a general feature parity but if you're going to interact with these projects often enough then it's better to stay on a single platform and avoid the context switch. Personally this only is already worth the $50-100 that our company is paying.

You can see that I am biased but something I would also like to point out: on more than one occasion github has prompted me to open-source things. When you reach your repo limit you're faced with a choice that you don't have with unlimited repos. There's a case where you don't want to think about it and just want to keep working as usual but for me space constraint is what keeps my home tidy.