Reading is quite a popular back-up uni for law, it's not too reputable, but if you work hard and choose not to aim too high in terms of future prospects of top law firms then i'd say it was good. If i were in your position(merely a suggestion) then i would put Reading as insurance and Cardiff as firm, this is because Cardiff is ranked higher like overall (whilst having a better reputation) ->and i'm a bit biased in that my law teacher studied at Cardiff many years ago and although the man has an odd teaching style, he is somewhat of a genius which i attribute to Cardiff uni. It is fine whatever you choose but you don't want to look back on your opportunity to go to Cardiff (or any others) which may be a little harder and not tried to get in =]