briantinnion has called this one spot on, the fourth level college thing buzz is still there but less free booze than back in the mid 00s. Although 1 or 2 of the big 4 are ridiculously busy and are throwing around a few free pints to keep the minions happy-ish.
If you're happy enough with what you've seen during your co-op I'd commit to getting the qualification. As the others have said it's a great qualification to have and you'll still be quite young when you're qualified(unlike me for example but everything's relative). If you don't fancy it then you can fuck off and do something else, or travel and get work relatively easily.
The exams have changed since the other CAs on here sat them and are way fucking harder now with pass rates between 30 and 50%. Looking at the past papers from the old syllabus its easy to see why the country is in the mess it is with some of the clowns that scraped through the handy exams calling the shots.
CAP2 is a proper cunt of an examination. Doing the masters gives you an exemption from that so it may be worth it, particularly if they'll pay for it which I presume they would. Then again it's a tough enough year and a few punters I know who came from the masters struggled badly with the case study nature of the new FAEs, which is ridiculous because there's a full year to adapt but people who'd gone through it at CAP2 grasped it a bit easier. There's plenty of study leave so it's well doable.
My preference would be to go straight into the job but it depends on how much you like college I suppose.
At the end of it all you'll join and elite club with Rocko, briantinnion, Bandage, farmy and Clarkeycat. Truly a wonderful feeling.