well Memberpress does basically everything except content protection much better than s2member IMHO - and there are countless 3rd part integrations available. PMP I'm really not sure - I would not use it - seems way to limited
I haven not fully dived into content protection by memberpress - as memberpress easily allows s2member to be used for that through their user roles plugin..
Role-O-Matic is nice, but I do not see how it can be properly configured for subscriptions - if at all. It does work for one time payments and allows to differ between renewals and new checkouts. I don not think Role-O-Matic, Woocommerce Subscriptions, and countless other plugins can compete for a membership site with Memberpress,
while ThriveCart, Quaderno.io orTaxamo and s2 for content protection are all essential tools that can be pretty well integrated with both Woo or Memberpress.
Also if membership plugin would only be about payment processor integration - then I would continue using it. However email management, reliability (very poor for s2member if 0.5% of payments are simply dropped by s2 even though showing up in the logs as received as s2 has not adapted to newest API of stripe and paypal since years, much much worse like 50% for stripe subscriptions not demoting) of demotion, sales funnels, and email system are ale not up to current standards!
No membership plugin is able to send proper invoice - but taxamo or quaderno.io for the best invoicing system is 100% working with memberpress while not fully reliable with s2member. And that's not even talking about s2member's weakest point - the UI of their proforms.
Memberpress will need some GDPR adjustions due to using quite a lot of 3rd party integrations - if your business is based in Germany I would say it will mean no use of website before accepting one of those dreaded GDPR checkboxes. Otherwise you can simply note that the devs have thought and tried out everything they implement - while with s2 countless times i've thought I freak out about how unreliable or wrong things are working. But yes - content protection (except drip) is simply great with s2.
BTW - if you're afraid about s2 not updating - at least their is Optimizemember (part of Optimizepress)- that means s2member with actually working support and moving over is very easy. I'm still not sure I will really manage to integrate my users into Memberpress - but if I don't succeed than the path is clear - at least get rid of s2member in favour of Optimizemember. The price is little and I'm pretty sure if you provide them the logs with bugs (e.g. members not demoted because system decides the API notice is unimportant) they will solve it - while s2 does nothing here. Most of it is identical ot s2 anyhow.