I guess I will do a bit of a write up on my experiences with Zero Suit Samus, though keep in mind I'm a scrub and still learning lots, and playing against scrubbier opponents.
Firstly, unless really well timed, you can't dodge ZSS fsmash with a roll behind like the way you can punish most forward smashes. Her hit box will still rage you behind her. (This has been nice though, as it keeps me on my toes, and ensures that I don't rely on rolling behind to punish attacks, which was probably a hugely bad habit of mine.) You can block it, but due to it's large range and knock back, it puts you well outside shield grab range, and I've been told that a wavedash grab will punish it.
Secondly, getting above her is usually a bad idea due to ranges of her up special and her upsmash, but it is extra dangerous with platforms like lylat or warioware. (I swear, Wario ware was like made for her.) as she can alternate upsmash and up special to pillar you. (Which looks cool as ****, btw)
As with other characters playing against her, we really need to abuse our recovery options to sweet spot the ledge, as simply using up special to get back will usually get a dsmash>dsmash>fSmash combo directly back offstage and probably to death.
Watch for the Paralyzer + Followup as ZSS can cancel out of her fully charged neutral B into a run. This is easily countered with cape, but can be quite devastating if you don't.
My ZSS player doesn't usually followup with up airs after knocking me up, but that is a thing.
As for approaching, I find leading in with fireballs works just fine, but again, my opponent doesn't usually try to clink with them, so I'm not sure of the options ZSS has available here. Also, SH down air seems to be a good angle as it can avoid the fsmash and can be L-cancelled into tilt combo's.
Ledge guarding has been discussed briefly, but getting down to the ledge, falling away and throwing out a Neutral air should stop her from zipping in on her tether. I haven't been able to do this yet, as my opponent hasn't fully gotten the hang of ZSS recovery so there is a 50/50 chance she just doesn't tether back at all.
On a more personal note, I'm just learning wave dashing now, and it feels beast to bait out a f smash, wavedash back into a fireball, and start combos from there. :D But that's just me enjoying learning stuff.