Nah i don't see it, jiggs looks by far the easiest to learn to get to a mid level.
There's a reason it took years and years of play for jigglypuff players to even start winning tournaments. Jiggs SUCKS at low/mid levels, she's so slow and floaty and lacks a good approach that you're basically required to be really really good with spacing and pressure to actually compete with other more solid characters.
Also at mid-level jigglypuff players tend to spam a lot more than most other mains I find, which is just a lot easier to deal with since they overlook a lot of openings they create without even realising it.
lol! Made my day.
define mid-level then decide....
This.
The question is really ambiguous. What is "best for mid-level"? I don't just mean skill level. I also mean stuff like, best for improving with, or best for placing with? Mid-level vs who? Vs other people of your caliber or vs top players? (this makes a big difference I find when, e.g. I think at a low level marth vs fox is strongly in marth's favour but it's obviously not the same case with a good fox)
For example I think Marth is very effective at a low level vs other low level players, when I first started playing I dual mained Falco/Marth but mostly used Marth in tournament because everyone at my level was REALLY bad and I could beat other people who were using spacies by spamming shffl fairs/nairs and just edgeguarding with fsmash/shield breaker. However, when I played better people I usually just went falco and did slightly better lol. I found that my marth did worse vs good people even though he's harder to combo because of the speed difference.
Despite how well I was doing vs other people of my level, I wasn't actually improving much at all. I don't think Marth is easy to improve with at all at a low level, eventually lots of your gay stuff doesn't work anymore and you need a solid play style to compete with people (I think it's difficult to develop a strong marth playstyle). A lot of people I used to beat just improved and started beating me (I got absolutely wrecked at ph2 for example I think I lost every set in my pool).
When I played Sheik I found that it was still easy to beat low/mid players since she's faster and lots of her dumb **** still works, I was beating people who I previously lost to with a character I'd played for a few days (compared to playing marth for a year and still losing...). vs high level players was the same story as marth though, sheik is HARD at that level when you're fighting good people, do not kid yourself by thinking you'll do better with sheik vs someone good because she's "easy", that's complete bs. But most importantly I found that unlike marth, sheik's set-ups were easier to understand, and she was significantly easier to
improve with, meaning I could slowly create a solid playstyle and compete on a higher level over time.
I think a lot of people should choose who they play on a low-level by thinking long term like this, rather than who it's easier to beat noobs with (like that really matters lol...)
I'm still trying to improve really badly, I play a lot every week (usually a little bit every day) trying out new stuff and figuring out what I'm doing wrong, but I think if I stayed marth I wouldn't have improved much at all even *if* I placed better with him at the time simply because I find it's a lot easier to improve with sheik. I don't know why, but no matter how much I focus on fighting falco I just blow vs him lol, though I hope that'll eventually stop.
btw I think the best chars at a mid-level are falco/sheik (I feel that these characters are strong choices to improve with), though they may not necessarily place better at first. I feel that jiggs is similar to marth (wrecks at a low-level but is difficult to improve with). Obviously though it can vary a little bit from person to person, e.g. even though I think falco is a good choice to improve with, it doesn't work out like that for me.
tl;dr I think you should choose a "low-level" character based on how easily you can improve with them, not how well you can place with them.