Congrats on the offers! I like Victoria's answer, and I will add 2 more anecdotal points based on spending a short time in Dubai on case work and also having quite a few individuals having to be staffed on KSA projects due to a dry pipeline
- I saw many, many consultants (and also corporate professionals) fly in from KSA to Dubai for the weekend, and rarely the other way around
- Getting cross office staffed on a KSA project (from another system) was often the least preferred option for many people. In my previous T2 firm they even came up with a special recognition award for consultants that had spent significant time there
I have not worked in KSA itself and the above was many years ago, so things might have changed since then - best to speak to people currently working there.
Lastly, since internships do lead to full time offers, and if full-time location is the concern, I suggest to network and speak to people in BCG KSA and check how many consultants previously started in KSA before transferring to Dubai (ask them is this difficult to do, how long is the wait etc).
Either way, both are great firms, and in the mid-long term, at least in BCG there is always an opportunity to do a transfer.