Target Masters or Non-target PE?

Hi folks,

I would like to ask you for your opinions on the situation that I am currently experiencing.

Unfortunately, my undergrad degree is rather poor (state uni in US) so I had applied for a couple of masters programs in finance at top unis in UK in order to maximize my chances to get an offer from IBD/PE in London (I am EU citizen) and I got in to Oxbridge for 2014 intake.

However, a couple of months ago I have started an internship at a mid-cap PE fund (less known) in London. Recently, they gave me and offer assuming that I would give up on my masters degree at Oxbridge.

What are your thoughts? Should I take the offer and consider target MBA later or should take the risk and hope (with Oxbridge degree and London PE experience on CV) for "better" offers from bigger funds/top tier investment banks?

Thanks in advance!