10% of 394 verified TWSBI Diamond 580owners don't recommend it, and 1 describe specific problems — based on real owner comments from Reddit, enthusiast forums, and YouTube.
For balance: 77% recommend it. This page collects the complaints so you know what you're signing up for — read the full owner report for both sides. How we score
“I vastly prefer my ECO to the 580. I ended up selling the latter, it just didn't feel or write as well, but the ECO just feels right and doesn't lose anything if you ask me!”— @markdryden8240 on YouTube
“I STILL don't reach for this pen. The grip is ridgey and slippery (even though my fingers are dry). So, those are 2 strikes for me.”— @dailycharmaddict on YouTube
“I have had the 580 and the Vac700R. I was not a fan of either.”— @paulmchugh1430 on YouTube
“Don't like the looks of Twisbis not for me but still a great video.”— @PeterLove-oc7ys on YouTube
“does the 580 write so much better than the Eco to justify it's price point? My answer is No.”— @arcboy2011 on YouTube
“TWSBIs leave me cold, which clearly makes me an outlier.”— @ichirofakename on YouTube
“I would avoid the Diamond 580 ALR. I have two, and both grips have corrosion problems depite the coating.”— @themetadaemon on YouTube
“I have both and also choose the Eco over the 580.”— @BlushnBlue on YouTube
“A few days ago I discovered some cracks in a TWSBI diamond 580 nib B.”— damiendays on Reddit
“Can't recomment TWSBI580 as mine is so problematic in real life(on paper it looks like a steal)”— iam7head on Reddit
“I recently bought my first TWSBI Diamond 580 in Fine and was disappointed how scratchy it felt.. whereas my Pilot Metropolitan is as smooth as glass.”— tialoc01 on Reddit
“I put Robert Oster Shake n Shimmy Envy in my TWSBI Diamond 580 ALR <F> and it clogged by the end of the first sentence!! I suspect the fine nib didn't like it.”— jaysouth88 on Reddit
Not complaints — practical notes from owners that didn't affect the score.
“I have one TWSBI, the diamond 580 in EF and yeah that line is probably equivalent to a Japanese MF, I'd say and pretty wet.”— Lucky_End_9420 on Reddit
“I found using my Pilot Custom 823 F would bleed through my Cousin but my TWSBI Diamond 580 F wouldn’t.”— OtheL84 on Reddit
“The TWSBI Diamond 580 EF is pretty fine, in my experience. I wish I had gotten mine in F instead.”— Violyre on Reddit
“So I have since switched it into my TWSBI Diamond 580 with stub nib and it’s working fine”— lbr218 on Reddit
“mine didnt break on the threads but on something in the inner collar maybe because I manipulated the piston even when the capped... this means to say TWSBI has some damn good seals”— anonymous on Fountain Pen Network
“I ended up tearing the thing open with pliers and by that time the grooves had been deformed and the pen isn't usable anymore the way it was intended.”— anonymous on Fountain Pen Network
“Over torqued the end cap while filling and heard a crack. After that, the cap would no longer completely tighten back down. After offloading the ink and inspecting, I found no damage. I must've skipped a thread.”— anonymous on Fountain Pen Network
“I have a diamond 580 and the 823 both in medium and I can say the Pilot writes wetter and broader than the TWSBI.”— freefisheater on Reddit