Which plugin for members area?

I need to have some pages (or possibly posts) on a website restricted to members only. As far as I can see, I can’t do this using WP roles (but please tell me how if I can!) and will need a plugin. So many show up in a search, I don’t know which to try and would be grateful for recommendations. I don’t have time to try out too many of them myself!

The website is for an amateur choir. So top criteria are

Cost. Ideally free though a small one-off payment may be OK. I don’t think the choir can afford ongoing paid support. But if there was a low-cost support we could access one-off if we run into problems in the future, that might be OK.

Simple to use.
While I’m happy to learn something more complicated, if something happens to me, one of the committee needs to be able to manage the site. And I won’t be doing it forever.

All we need is to restrict some pages or posts so only choir members can read them. I don’t think password-protected pages with a single joint password is a good way to go, so I assume people will need to register. Ideally, we need two categories: choir members and committee members. (Or just one category and I’ll need to teach the committee how to use Google Docs or similar!)

Longevity
It’s important it is updated along with security needs and WP updates. If it stops working while I’m still managing the site, I know I can hunt for another plugin. But it’s unlikely my successors will be used to using WP, used to using the WP support forum and finding and installing plugins. So I’d like to find a plugin with a good track record and developers likely to be around for a good while yet.

Good support. Again, because I won’t be around forever.

Small file size.
Not so important, but the host I’d like to move us to has a free package with 50MB disk space and there’s a fair chance that’s all we’ll need. If there’s a choice between two equally good plugins and one keeps us within that and the other goes over, that would influence my choice. But I do think we can pay for hosting so the other criteria are more important than file size. Difficulty I’m having is that I can’t find information about file size on the plugins I’ve seen so far.

I’m not sure how to go about finding out these criteria for the long list of member plugins there are. I wondered if a proxy for some of them is number of users. Do I look at at least 10,000? 100,000? I’m looking in support forums to see if people’s questions are being answered. And in changelogs, but only some developers date these, so I can’t tell from the others how long the plugin has been around. I do know to make sure it’s been updated recently.

I don’t ask much, do I?! (cough, cough)

Some I’m wondering about, mainly picked as have lots of users:
Ultimate Member
WP-Members: Membership Framework (except it blocks by default, which I’d rather not have.)
Members

Any recommendations? Or pointers to how I find out the information.

Thanks for help.
Clare
PS. Yes, I know, I’m asking a lot and don’t expect there’s something that meets all criteria perfectly. But no harm in asking! And hopefully people with experience with some of these plugins will be able to tell me what they’re like.