The upside is that you are your own boss, so you can, in theory, pick and choose your work.
In reality, it's not quite so simple. For a start, unless you are well known, companies will be reluctant to hire you until they know you well, and you won't get the decent work straight away. You'll likely start off by getting the piss-up jobs that nobody else wants to do, and the wage rate will be "take it or leave it". Then there's the paperwork. You will be expected to show the taxman and other Government departments that you are, in fact, freelance and not just playing the system by showing invoices paid by a number of coach companies or other businesses. There's a bit of a catch 22 here, in that you won't get the self employment certificate until you've been self employed for a while.
If you are self employed, you need to sort out your own tax and NI, though you can claim stuff against your tax that us wage slaves can't such as mileage from home to work, part of your mortgage payment to account for your office space and such like, and while you can claim a discount on your council tax for office use, you will be replacing that with business rates. You are also responsible for your National Insurance payments, you get no sick pay unless you set up your own insurance, not even SSP, and you are not entitled to paid holidays. It almost goes without saying that you are not entitled to unemployment benefit, so if you don't work, you don't get any income unless you fight the DHSS or whatever they're called this week, tooth and nail for it. You will also find many coach companies, having been bitten before, will only pay you as PAYE through the books, so you need to make the necessary adjustments in your tax return. It is strongly recommended you pay an accountant to sort these problems out. There are drivers' agencies out there who can deal with some of the faffing about for you, but they take a commission on your fees and one or two have a very bad reputation for not paying on time or at all.
Mind you, it works for some, and they enjoy it, so good luck...