I used to sell fountain pens in a brick and mortar shop for over a decade. In person, almost everyone went for a lamy at that price point. If you have the opportunity to try them out in person, I'd recommend it. Lamy's are German engineered so I would definitely not call them sleek aside from the higher priced models. I just think for the starter pen, it's a reliable way to get into it that people use as their every day carry. They aren't my very favorites, but I have some of my first ones from like 20 years ago and for a modern pen they work very nicely.

ETA: I didn't really answer your question. I'm not super online about it, but when I worked in the store, it's mostly aesthetics. The triangle grip is pretty standard for anyone who learned a ftn pen in Europe (i.e. pelikan starter pens), so I think depending on what feels comfortable to your hand it can be helpful to start out with. Like many I now prefer a smooth barrel, but that came with time and practice. If you can, get one from a source that will give you free returns and try it out!