Perfect pen, for quick notes or long writing sessions, due to its grip and weight! I never liked "thick" grips, even though they are more comfortable, because I would lose accuracy and my letters wouldn't look good. With this pen, I can write good letters (it helps, especially for me who writes relatively slowly and doesn't make huge letters, so I always go for a 0.5mm pen) and the grip is super comfortable, it doesn't slip and it doesn't make you press the pen with force like others! The ink is perfect! Now, about the thickness of the writing, for a pen I wouldn't say it's 0.5mm, maybe it's more like 4.5mm but this sometimes varies from pen to pen, so it also depends on the pen you usually write with. The body of this particular Energel is much sturdier than the more expensive Energel pens that usually break in the middle, where the refills screw in! This one is solid, all one piece, without moving parts or points that will wear out or break after a little use. However, this might be a negative for some, because others might want to change the ink like the slightly more expensive Pentel Energel models, but I mentioned that those break...so I give this model a higher rating, it's truly a reliable, correct, and convenient pen. This, the old Pilot V5 (the new ones break immediately and don't write...or they leak ink at the same time, unfortunately) and the Pilot G-TEC-C Maica are the 3 best disposable pens I've ever had!!!