Hey! I'm a third year nursing student at bucks so can give you a quick rundown..
If you live in Uxbridge, you have a 2-15 minute walk to uni depending on whereabouts you live in and around uxbridge. Quite convenient and saves you money/time spent travelling, but a walk either way.. There's no campus so you can feel sort of excluded from 'normal' uni life at times..
Uxb is generally better if you're on placement locally as the underground station and bus station are quite central to most surrounding areas.
However, you get more for your money in terms of housing in HW - generally bigger rooms for less money, and theres more of a 'uni feel' with the SU bar etc. - you'll probably have a lot more fun there.
There is a campus link bus that goes both two and from the campus free of charge on the hour, but can be quite busy at peak time on uni days.
If you have any more questions feel free to ask