Okay I’ve used both but in Australia so no brand opinions, never seen the ones you mention.

Pantyhose has to be of good quality (ie. Not from mystery brand on AliExpress) or they will constantly slide down, which is very annoying. They will also ladder and tear more easily rendering them single use basically. So get a reasonable brand. You will have to try and see.

I’m presuming you have female anatomy like me. Crotchless pantyhose can be a better option for the toilet if that’s your concern, but that depends on how neat and tidy you are with your business. I couldn’t. I’d be getting piss droplets on the pantyhose if I had to go wearing them. For me that’s too gross of an option.

The main advantage of pantyhose is that it’s easier to put on (think of your routine if you need this on a daily basis), it usually stays where you leave it, and it covers the whole leg. It’s also even all along, whereas holdups may show through the fabric of whatever other garment you are wearing if it’s tight enough.

Holdups as mentioned may show through the fabric. They’re also more difficult to get right, I’ve never bought holdups that stayed put without using a garter belt. If you have super firm legs then you may have better luck than me though . In my experience, the holdups either stay in place but dig too much into the leg which looks awful, or, they fall down a lot. So I’ve used garter belts, and here we have another variable which is that of the clasp+holdup edge types. The more discreet clasps are button type and usually don’t latch well on most holdups, they snap free when you move and your socks fall. The crocodile style clasps do bite and stay but, again, you can see the bumps through the skirt in many cases depending on the fabric.

For sizing, always err on the larger one. Unless you are super skinny. I’m not sure of your sizes, I use metric system, I only know I’m 5’7" and 64 kgs with a pronounced hourglass shape. And I’m usually a L, and when it comes to hosiery at least Tall. My sister is a few cms taller than me, and needs ExtraTall or nothing. So it sounds like you’d be extra tall/Large, unless you are very skinny and thin.

Hope this helps. Good luck with it