On edapt, there is a drawback in that you're not legally entitled to a rep in disciplinary meetings like you are with unions, however most schools will allow this, possibly as it would reflect badly on them.
...

Other than that, I would wholeheartedly recommend edapt based on my experiences with them. If legal cover and advice is your primary/only motive, it makes sense to join edapt as that's where all their money goes. Union fees go on all sorts of things.

I never needed legal advice when I was with the NEU. My wife did and it was hopeless. It took 3 days for someone to even respond to an email.

My first dealing with edapt was asking where we stood when Essex County Council cocked up pay. I emailed during my morning break and got a call at lunchtime.

And that was my experience throughout. Send an email and get a call within a few hours, sometimes within a few minutes.

I had a horrific time working for a headteacher who despised me. Edapt got her to back right off.

I had a meeting with her one morning (she denied me an edapt rep so I attended with a TA who took noted for me) and I wasn't ready for it. I'd lost my composure as soon as I got into work.

I got a call at about 8:20 from the person who'd dealt with previous issues who basically talked me through how the meeting could go and what I should avoid doing. I left that meeting like a boss.

So if you're thinking of leaving the NEU but want to be part of a union that's not led by Twitter activists, you're probably best off joining the NASUWT.

If you're only interested in the legal protection side of things, join edapt.

#quitNEU

And you do NEED legal protection in this job. Everyone is one inept/vindictive HT or one complaint away from a potential end to their career.