Sailor makes magnificent pens and inks. The Professional Gear Realo is no exception. It is, in the realm of Japanese pens, unusual in having a piston-fill system. This system is smooth and effective. The 21k medium nib delivers a nicely medium line, with just enough feedback to connect me to the feeling of writing. It is a handsome pen, an adornment to desk and hand. I appreciate the ink window being visible when the pen is capped -- I can see at a glance the ink level. I might add that the packaging, a cardboard box, was understated but elegant. In all, I am happy to recommend this pen to anyone who can afford it.
These pens are light, well manufactured, and have nice nibs that are a little springy with pleasant feedback on the page. My recent experience of Sailor nibs is that they are improving in terms of how smoothly they write out of the box, and the medium nibs seem fairly consistent (I have recently purchased several of these). Like all higher end fountain pens, these are a little pricey even straight from Japan, but in my view they are the closest thing to value for money in higher end fountain pens that I am aware of.