I was a student member, but cancelled after I graduated. For $200, I somehow expected that I'd have complete access to their publications, but it turns out that you don't get that. You've to pay extra for access to their digital library (which you can't get without a membership), and even then, the access is limited - something like 25 articles a month (which don't carry over) for $44/month, with a minimum commitment of 6 months. The only reason to keep their membership is access to their journals (especially those published in the '70s and '80s), and since I already had access via my workplace, I didn't think it worthwhile. You're basically looking at $733/year for limited access to their publications.
Another option is to join a society within IEEE (in addition to membership). This gives you a substantial discount on subscriptions to publications sponsored by that society. However, I found that I needed to join multiple societies to span the publications I was interested in, and it was just not worth it.
I don't know where you are getting your numbers from wrt ACM at least. Last time I checked it was ~£100 without DL access, and £200 for membership + full DL access. I think that is a pretty good deal. It costs money to run a digital library, and you have to remember ACM isn't really comparable to profit driven publishers such as Elsevier etc.
Another option is to join a society within IEEE (in addition to membership). This gives you a substantial discount on subscriptions to publications sponsored by that society. However, I found that I needed to join multiple societies to span the publications I was interested in, and it was just not worth it.