Pros
It's a good start point for people with no skills, qualifications or working experience on CV in the UK, then you can move on to something better if you are worth of it.
I've recommended Oakam in the past (about 6 years ago) to friends and family.
Nowadays I don't recommend to my worst enemy.
Cons
Oakam was a good company to work when I've joined it, it was still small, the CEO had more touch with all the employees with his monthly breakfast and briefing and would listen to our suggestions of improvement.
Then, ambition bitten Frederic and to achieve bigger goals he had to get funds from big banks and run under their rules. Banks are greedy and blind, they only think about their profit. And then, Frederic became one of them, driven by greed, blind to his employees and anything in between. The company became more "professional", nicer HQ, nicer furniture, better systems, brand and stores revamp, however, the most precious asset, his employees, were overlooked. The fuel that ran Oakam's "engine" were overlooked and we all know what happens when an engine runs under the wrong fuel. It eventually breaks.
We lost bonuses (you would get yearly anniversary bonus after 2 years in the company for commitment and loyalty, then it changed to 5 years and 10 years only. Also collections department used to give bonus according to the team's hard work to get those defaults paid again. No more)