If someone were given a snapshot – literal knowable attributes of someone else, that is real knowledge. That of course does not constitute knowing them personally. We have that about God, but he is also personally knowable and lovable through his direct interactions in his children’s lives, but childlike trust and ingenuousness is required.
There is direct experience available, constituting “I” contact, though. For some, putting their faith in him starts with believing the truth revealed in the Bible and the testimony – the honest factual reports, present day or past – of others, some of whom they may even know personally, like parents, friends or relatives. This in turn leads to the experience of his recognizable presence in their hearts and minds, changing their heart’s desires, goals and worldview. Others have more radical and externally observable objective experiences. I certainly don’t want to impugn the reality of inward experiences, such as Sy Garte’s. C.S. Lewis’ conversion experience comes to mind, too. (I wish I had a collection of the accounts of both kinds. I needn’t mention Maggie for you, of course, but I will for the sake of the unimaginably few who see this who aren’t aware of her account. 
) We could discuss whether or not the adjective empirical applies to the external evidence, though, couldn’t we, T. @T_aquaticus Sometimes in a Christian’s experience they are given objective evidence they don’t want, not to convince them of God’s reality, but to “direct their steps”,* like Rich Stearns. (The sequence of God’s providential interventions in my med school experience included some like that. Maybe I should include my nephrectomy, too.)
Since we have knowledge of his beauty in creation demonstrating his artistry and imagination, and knowledge of his cool providential interventions in the lives of his children demonstrating his sovereignty and power over time and place, who would not want to know him personally?! (Not to mention that is unwise in the extreme.)