Big hint:
Look beyond the uniforms, the Starbucks Cafe, the sims and the modern buildings and classrooms and understand that ultimately its YOU that will earn yourself your ATPL - all the equipment and funky gear / image that Oxford projects won't help you one bit if you're not prepared to put in the work.
The real question you should ask is "will this environment allow me to complete the ATPL in a way that I find most beneficial and that I am comfortable in?"
You could arguably complete the ATPL study side of it in your back garden shed if you were committed enough and 200% made best use of your available resources. OAT allows a VERY rigid and structured framework for you to study in, which takes the self discipline element largely out of the equation. At 60K for the basic course, it should at least do that!
Lastly, OAT might offer you a very slight advantage with the major airlines who tend to source newbies from them. Don't over-estimate how marginal that advantage may be though!