For an apprentice line kit from them, it's actually pretty stout. When posted, it's still shorter overall than a slimline. I can't say for sure that the ballpoint twist version is the same length, but I imagine it is. But it's a thicker pen than a slim or trim/comfort line so to my hands it's more comfortable.
I haven't done any lengthy writing sessions with it, so not sure on the fatigue factor with the shape of the tip end and I forgot to bring it to work today so I'll have to follow up on that. The only thing I can say is that they are on sale right now and grab a few of each type to try them out. I have a few Manhattan click pens lined up to turn as well to get an impression of those.
About half way through drilling I had a thought to do it as a closed end but realized that with that short length, you need the postable cap to make it long enough to write with. I may try a closed end version with a longer body and keep that kit cap.
Also they take a shorty style refill, so be prepared to offer refills to your customers since they are likely not available at the local office supply store.