Yes. I am a member, and have been part of the committee, but I stepped down last year when they went to womxn rather than woman, and I don't feel our values are quite matching these days. It's a multinational corporate.
It has been immensely useful; they've run info sessions on different areas of the business, most of which I have nothing to do with on a daily basis. They've also profiled women leaders and had them discuss their career paths. I was seconded to a project for 18 months because of one of the woman I met through it, and her seeing my skills. I've had access to mentoring, training and conferences through it, and been able to organise events and teams through it, opportunities I wouldn't get in my day job. I've also had access to other people to advise me when my own dear department were being arseholes (very techy, and I'm the only woman.)
They have recently (since covid started, i think - time's less memorable in recent years,) changed the rules on how the Employee Resource Groups are run, which means those of us not in senior positions now have fewer opportunities to be involved as leaders, and it also seems to be moving back to the US forgetting there are also thousands of us in EMEA, AsiaPac and LatAm, and we don't all operate exactly as they do in the USA, nor have the same employment laws or societal pressures to deal with.
I think you need to know what your aims are -don't focus only on execs - people lower down need support, and to see there are career paths. Is it about mentoring, sponsoring, networking, education, supporting external organisations... ? It can be some or all of these things, but some of this depends on your budget (we had a brilliant women's conference a few years ago, but not been given the budget for that again.)
Some of it will depend on your industry- we're in tech, so there are known issues with women in STEM, and part of me thinks we don't need to do anything for the women, but should be educating all the men to see we are valid members of the workplace, just as capable technically, managerially, etc, if not more so.
And a lot will depend on who you have to work on it and what time you're allowed to give. There's no point trying to run 20 brilliant ideas for events if there are only 3 of you and you're only allowed to give 2 hours a week to it. Better to do fewer things really well and build up from there, and show the value. As other posts show, it not always a good thing, but if done well, can really enhance the working environment.