10.11.1, 10.11.2, and 10.11.3 brought no relief. Then, 10.11.4 improved its operation substantially. SDHC cards would work for several sleep cycles before being gone to the wind. Sometimes, just to be assertive, OS X 10.11.4 reverts to its old ways. It likes to mess with me.
I have never had El Capitan freeze on me BTW.
10.11 El Capitan brought a whole new USB software support and some people have claimed various fixes for the SDHC issue, use a driver for an external reader, muck with the control files for USB, etc. The reliability and security of these fixes is always dubious.
Other problems also came with El Capitan (for me at least). Calendar spins its color wheel cursor at me as type in new events, it takes 5 or more seconds to respond to a single character. I've played with the various iCloud settings and mitigated the problem, but not by much.
El Capitan came with a number of "improvements". The Notebook application was supposed to have numbering and other new features. I tried them and couldn't believe how poorly the features worked. I looked for an alternative and discovered the best application on the planet, Microsoft OneNote. I now use it on my Mac, my iPhone, my Chromebook, my Windows bootcamp partition, and at work on the PCs. Highly recommended. Best app I've ever used.
The myth of "it just works" is a myth. I curse my Macs oddities way more than I curse at the PCs at work, except for cursing at the work itself.
I toyed with restoring Yosemite from my Time Capsule. I finally did a few weeks ago, but to an external Firewire disk. Then I found that using an external disk for booting OS X doesn't work that well. It won't wake from sleep well, for example. But I tried, I just don't want to blow away the internal disk for it. Any besides, it took 6 hours to build that disk from Time Capsule as it restored 650MB of media besides the OS plus all the old versions of my software. You have no (minimal) control over Time Capsule.
There is nothing Apple sells that I want any part of anymore. The new iMacs look just like the one I've been using. Maybe my problems with El Capitan are due to my computers age, but I buy Apple because they've historically given me good value and lasted with full software updates. Like for seven years now.
I may have to switch to Windows one day. Don't tell me about Linux, I use it all day at work too. Not Ready for Prime Time.
So, I guess I'd rather bitch than switch.