Thanks CPTBadass, it's nice to finally chime in after lurking in the thread for a while. (became interested in fountain pens after I got sent a Pilot Metro from massdrop). Since then I've tried the Pilot Metro, Lamy Safari, Noodler's Konrad (there's also the Varsity, which I wasn't a fan of).
I love the TWSBI too, as it really hits a good spot between feature/price. It did take alot of futzing before it became my favorite pen. Misaligned tines, flow issues. Ef being still too thick for my everyday writing. But the piston mechanism and ink capacity was a great draw that made me determined to make it work, which led to ordering a #5 needlepoint from a nibmeister and putting it in the TWSBI; after smoothing it a little, it writes lines similar to that of the pilot hi-tec 0.4, and can be used on the reverse to write hair-thin lines. (which was why I had the extra ef to play around with).
caveat; I often have to write lousy printer paper for work, so thick nibs that lay down loads of ink are pretty much impossible to use. Also, I'm a southpaw, which means anything that lays down a thick, wet line is going to get smudged. The needlepoint is pretty much my only pen I can use on all sorts of paper + write at normal speeds without the paper getting inky dots all over. The Safari is a close second, but I do get slight smudges occasionally, even using reasonably dry inks.
Other random thoughts;
Out of the box, the Safari was probably the best writer; much better than the TWSBI, which was actually problematic. I did minimal tuning on mine, mostly smoothing and made it finer. (Western EFs are still not fine enough for my preferences). I would've been satisfied with the Safari if not for the crappy convertor/capacity; well, not exactly crappy, but once I got used to how much ink a piston pen holds....
The Konrad was fun, but impossible to use on crappy paper, and the build quality leaves a lot to be desired, but it was a great flex pen modded; much better than the TWSBI flex, which is decent but not amazing). Although, to be fair, the noodler's nib was extremely smooth to write with, the lines that it laid down was pretty similar to the pilot varsity I've tried. (I'd modded the noodler's for extra flex too, but days after I got it perfect, it got ruined after a nib first drop to the ground. /sigh.) I might get another Ahab/Konrad in the future for a nice flex pen, or get a TWSBI VAC700 try to fit a noodler's nib in.
Pilot Metro - my first proper fountain pen. Very smooth writer. the M sized nib and ink flow had the same problems as the Noodler/TWSBI F; ie. ink feathering all over the paper; but in fairness, it worked great on my personal notebooks. I think I would've probably liked the Japanese F (although I think my actual preference would go towards a smoothed EF). The squeeze convertor is a big minus, although I guess it was understandable given the price point. I ended up turning my metro into a stub after an early screw up learning how to grind nibs, but I might try getting a Pilot Penmanship for a nice EF and swap the nib into the metro.
Between the Safari and the Metro, I've pretty much switched to using a separate syringe to fill my pens for less mess.
