I think you have to divide positions on this issue into three parts.
1) There is no spiritual reality--everything is material. People who have religious experiences percieve nothing real.
2) There is a spiritual reality, but it is not personal.
3) There is a spiritual reality and it is personal.
It seems a lot easier to use religious experience to show that 1 is false than to show that 3 is true, since many who have religious experiences (which have a lot of commonality with theistic experiences), perceive a nonpersonal spiritual reality.
