Try them both and you won't forget the difference.
898, as I recall, was first a designation of how the cigars were boxed. 8 on the bottom, 9 in the middle and 8 on the top. Those are the boxes with the rounded out centers.
Ashton has the line called the 898, a good cigar but not to my taste.
There is also a mfg of cigars made in Jamaica called 898.
I have absolutely NO idea why the 858 is called that, but it is a really good cigar.
My .02
Dan (JustDanD)