Unfortunately, I can't see any way a non-Christian can decide which, if
any, is the real Christianity. A Christian presumably makes this decision
by seeing which ones follow his idea of Christianity, which he believes is
provided him by God (his idea, that is). I have philosophical problems with
this approach, based on the human tendency towards self-delusion -- but
in any case, valid or not it isn't available to me!
I can't claim to accept anyone as christian who claims to be -- but if I
had to decide between the Catholic church and the unorganized evangelicals,
the Catholics would win hands down by historical precedent.
-- David Dyer-Bennet