First, the rolling ball style ink can smear a bit with a heavy hand; a problem particularly for left-handed writers

Just let them warm up a bit before you use them.

If you don't, the tip might bleed a bit of ink onto your clothes

Their ink takes a bit to dry, and it can bleed onto the previous page if you close the book before the ink is dry.

I especially like the fine line width of this pen (it seems a bit hard to find anything in a .5 mm, which is my preferred writing width).The pens write smoothly, and I haven't encountered any breaks in the line or sticking of the point

A bit expensive.

May even have improved my penmanship just a bit!

I used to buy packs of the pens, which are a bit more expensive than the average pen.