I fenced in high school and college.
It’s a good lower-body workout. You spend the entire time with your legs flexed, so your thighs will get stronger. It’s not great for sustained aerobics in my experience as it’s fairly stop-and-start. But if you do a lot of footwork drills and parry-riposte drills (which you will, if you want to get any good), then it can certainly wipe you out.
It’s moderately expensive equipment-wise. You need a mask, a weapon, some tools and whatnot for replacing blades and electrical connectors and things. You need leggings, jackets, gloves, and if you are fencing electric with saber or foil, a ‘lamé’ (metallic coverlet that defines the areas where a touch is valid). It won’t break the bank but you should be prepared to lay out a couple hundred bucks, I should think. Also, fencing clubs (also called salles, because fencers like to use French words) may have memership fees. All that said, I somehow managed to do it when I was dead broke in college.
Fencers tend to skew geeky, D&D-y, and techy, so they’re generally a pretty good culture fit for Qt3 types. Most of the real life friends I made in college were made through fencing, and a few are still my friends decades later.
Is it fun? Umm. As with anything you set out to get good at, it can develop a fascination. You want to get better so you practice. I used to randomly break out into footwork practice all the time in college, which I’m sure made me look ridiculous. When you execute correctly on the things you’ve drilled, there’s a rush. That said, I do find there is a difference compared to the only other sport I have played extensively, tennis. In tennis, the core physical act of the game – striking a ball with a racket – is for me intrinsically pleasurable. In fencing, advancing and retreating and lunging and parrying don’t carry that same pleasure. So it’s less ‘fun’ in that sense, I think. But that’s very much a subjective call.
Fencing is not easy and it is very footwork based. A lot of the drills are just about maintaining distance and building up leg strength, and you don’t even need a weapon in hand to do them. When you actually start to do parry-riposte sequences and then actual bouts, you will find it is very different from stage fighting. The movements are much smaller and much less telegraphed. To the untrained eye it can seem as if not much is happening at all.
