It's not as heavy as the 580, nor as light as the Lamy Safari. In terms of length, it's nearly the same size as the Safari, with a slightly thicker diameter. The plastic on the Eco doesn't feel as cheap as the Safari, but it doesn't feel as solid as the 580. It's very much an inbetween kind of pen when compared against the Twsbi 580 and Lamy Safari. The ink capacity is much better in the Eco than the Lamy. I think that definitely helps to give it a heavier feel and a little better balance. I write with almost all of my pens unposted, and the lengths on the Eco (and Safari and 580) make it very easy to use unposted. The balance is nice as well. It's definitely a very nice pen for the money, especially as a piston filler and a pen with a stub option. If you can spare the extra $25-ish bucks to step up to a 580, I'd probably recommend that pen, just because it feels like a more solid pen with a little more weight to it, and it looks visually more appealing to me. But, if you're on a budget and comparing it against the Lamy Safari, the little bit of extra weight and a slightly more solid feel would swing me towards the Eco. That, and I'm not a Lamy grip person. It fights my fingers.Corey, How does the ECO feel? Does it have a little heft or is it a complete feather weight?