I use 4 Kaweco Sports on a daily basis, each loaded with a different color, each for a different purpose. Three came with Bock nibs. The most recent addition came with a JoWo nib. Most of the pens were purchased via MassDrop. I would like to buy JoWo nibs in each size (except the italic nibs), because the EF I received on the latest pen is more in keeping with what I would expect for an EF. I don't see much of a difference between the Bock F and EF nibs in line weight, but the JoWo nib was very different. I experienced "baby's bottom" for the first time with one of the italic nibs from the Calligraphy set, but was able to fix it myself. It is now used daily, for underlining and highlighting (and the occasional, super bright and bold word). Kaweco AL Sport is my favorite pen, for several reasons, including the ease of taking it apart for cleaning (the feed unit is entirely friction fit in the plastic pens, and can sometimes be difficult/impossible to remove, where it is threaded into the AL and easily removed with a few turns). The only pen I've used so far that I didn't care for was a Lamy Al Star. I loved the color, which it the main reason I bought it, but it is very finicky and I don't like the feel of it in my hand. My general rule of thumb on pens has been not to keep any that aren't being used regularly (unless they're "art supplies" vs writing tools, like dip pens and technical pens). So, when I buy one, I typically get rid of one. I use 3 or 4 fills of different brands of inks (on various papers) before passing judgement on a new pen. After that, if I don't like it enough to replace one I already have, I'll clean it out well, put it out where I can see it for a few weeks, then try it again. If the problem is the nib, I may replace the nib or do a simple adjustment myself. If I still don't like it as much as what I already have, it gets "re-homed." Once I've purchased a pen, I owe it to myself to give the pen a chance. After that, though, I'm unlikely to buy another of a pen model that didn't make the cut.