We know that whosoever is born of God sinneth not;
but he that is begotten of God keepeth himself,
and that wicked one toucheth him not. (1 John 5:18)
We know that whosoever is born of God continueth not in sin;
but he that is begotten of God and keepeth himself,
that wicked one overcometh him not. (JST 1 John 5:18)
There are some interesting differences between the King James Version and the Joseph Smith Translation that should clarify for us what we can expect as we are born of God.
The KJV says that those who are born of God sin not, but the JST changes this to say that those who are born of God do not continue in sin. This shows us that being born of God does not mean that we won’t sin, but it means that we will not keep sinning. This provides for us to have learning experiences and realize we have been sinning so we can repent. Most (if not all) of us have mistaken traditions of nurture or mistakes of our fallen natures that we have to discover and root out, and being born of God doesn't automatically take care of that for us.
The KJV says that those begotten of God keep themselves and are untouched by Satan, but the JST changes this to say that those who are begotten of God and who keep themselves (from sin) are not overcome by Satan. This tells us that when we are born of God, we do not automatically keep ourselves from sin. This implies we have to work at it a bit (even if we have no desire to sin). It also tells us that if we are born of God and we keep ourselves from sin, we will not be overcome by Satan. That implies that Satan will still touch us (which I take to mean we will still be tempted), but that he won’t succeed at getting us to sin.
I think this bit of JST gives us the comforting doctrine that being tempted does not mean that there is something wrong with us. Part of mortality is suffering temptation. Even Jesus suffered temptation (though He gave no heed to it). Being born of God and keeping ourselves from sin will keep us from being overcome, and that is important in these last days when iniquity abounds. (See Joseph Smith Matthew for extra on this—He who is not overcome the same shall be saved.)
I also think the JST is important because it gives us the most realistic view of what we are up against, but it also gives us hope that it is possible to be born of God, to keep ourselves from sin, and to overcome the temptations of Satan.