Having been to a brick university before I can honestly say that studying with the Open University has been one of the best decisions I have ever made. The course materials are second to none and the O.U are flexible enough that if life gets in the way as it inevitably does, there are always options.
The weekly planner divides the course up into manageable chunks and gives you a good idea of whether you're staying on track. Considering you have an average of 6-7 months to complete a module, the amount of information you take on is extraordinary and can be overwhelming but when you look back and realise what you have achieved, it's a feeling like no other.
A word of warning though, be prepared to sacrifice your social life. The O.U can only give you what you're prepared to put in and sometimes you will have to prioritise studies over other more pleasurable activities but the rewards are worth it.
The O.U are supportive, but we are adults, do not expect to have your hand held throughout the whole course, especially beyond your first year. Tutors are there for support, but do not expect them to be at your beck and call, the majority of them have other jobs and cannot always be there straight away. Do your research into each module, if you don't realise you have an exam at the end of your module, it will be because you didn't read the description, not because the O.U don't communicate. The only reason the O.U has a reputation for being harder than brick uni is because you have to juggle work, kids, partners etc. The marking system is the same. Don't expect to sail through, it will be challenging. Pay attention to your tutor's feedback, it is the only way you will improve a grade, and when it comes to second and third years, don't just rely on the given course material, be prepared to read wider and work harder! Like most things, the O.U will only give back what you give in, and what you give will pay dividends!