I can't comment on brick universities because I have never had the experience, and the benefits of the OU have already been outlined.
In addition to the tutor support, many courses also offer tutorials in your area, something like 1 a month and these are well worth going to.
You do need a level of self discipline, to make sure you study and complete the work on your study calender, but Open University degrees are often held in high regard because of the commitment they show.
It has been said by some students on some of the OU forums (platform) that the marking is tougher with the OU, it's harder to obtain the high marks and a B with the OU may well be an A with a brick university, but overall, the majority of people are impressed with the OU by the time they have completed their studies.
You have as many rights as traditional students and can also join the NUS, and the open university have their own students association as well, where there are local branch meetings - OUSA.
There is support from other learners, your tutors and the regional office as well.
The website can be confusing, but to explain it in simple terms, choose the degree you would like to study, then look at the different courses you need to take. Some will be compulsory. From there, choose a level 1 course and you can register online. If you're unsure whether the OU is for you, do a short 10 or 15 point course. The points you accumulate can go towards your degree and you'll know if the OU is for you or not.
The funding is straight forward - there is a finance calculator which tells you if you're eligible for funding. If not, you can open a budget account and pay off in instalments.
You can learn and earn at the same time - study over 6 years part time, or, study full time, two modules (courses) alongside each other. Although this can be hard work and requires several hours every day, with little room for falling behind.
And I think that covers everything!