Q: Does publishing in an open access journal of a prestigious publisher have the same value as publishing in a subscription journal of the same publisher?

As an author, it is important for you to be clear about what you aim to achieve by publishing your paper in any journal. Try not to look for a connection between the publishing model of a journal and its impact factor. Ask yourself what you prefer – if immediate wide outreach is what you are looking for, an open access journal will help you better. However, if prestige is what you are looking for, a journal with a high impact factor will help you achieve your goal.

In this case, when considering an internal transfer to another journal of the same publisher, evaluate the new target journal against established journals in your area of research. Have your colleagues published in this journal? Has this journal been cited in previously published articles on this topic? In short, use the same parameters you would use to choose the right journal for your paper in the case of a transfer, too.

In the current situation, the open access journal suggested for transfer does not have an impact factor. While it may get an impact factor in the future, you don't know how long it will take and how high or low it will be. The fact that the journal is with a prestigious publisher will not ensure a high impact factor, as the impact factor is determined by the number of citations articles within the journal receive. 

So you need to think about how important it is for you to publish in a high impact-factor journal when making this decision.