What an appreciative audience here. (Coughing to clear my throat), Gentlemen. I've been in DSLR photography since 2002, and since then I have learned a great deal. Some from reading, a lot in fact. Some from my own experience, as in good and not-so-good purchasing. In the category of DSLR batteries, I will always recommend you purchase the original manufacturers battery. I highly doubt that Canon or Nikon make their own batteries. But I'm very confident that they control the quality standards with those companies that actually do make their batteries. Bottom line: I would never buy batteries from other than the manufacturer of your camera, and I urge you to do the same thing. Spend a little more at night, and sleep better at night. As a disclaimer, I am stating this as my own personal experience.

PS: If you'd like some third party batteries I've purchased over the years, let me know, you can have them for free.

I just recently received my new 5D Mark 4 and I'm enjoying getting acquainted with it. My initial impression is really VERY positive. I do have a question re using 3rd party batteries. It's no surprise that Canon is trying its best to make anything but a Canon battery uncomfortable. I noted that, when I insert one of my Vivitar batteries, I get the error message that says the camera can't communicate with the battery and it asks if the battery I have inserted says Canon on it. If you say no, it tells you the usual thing about not guaranteeing that the battery will work properly and it gives you the option to continue using it or not. If you continue, you find that the battery info in the menu will not operate, thus you can't see remaining capacity, shutter count, or recharge performance. Not a real big issue because the camera still functions as it should. The only other missing item is the little battery gauge that you normally see on the back and top screens is blanked out, so you have to wait until you run out of juice and the camera quits.

With the Vivitar batteries, I have always had excellent luck using them on 5D Mk 2, and my 7D Mk 2. Both provide normal information on the screens and there is no difference in performance. While it may be too early, I'm wondering if the Wasabi batteries that I see recommended so often on this forum have perhaps found a workaround for this issue, or if Canon has finally managed to make 3rd party choices irritating enough to force the purchase of Canon brands only for the 5D Mk 4.

Any recommendations, experiences, or solutions from those who may have gotten the 5D Mk 4 would be appreciated.

Another issue I discovered is that you apparently must use a pretty fast SD Pro memory card. I slipped in a Sony Class 10 card that only reads 40 MB/s and the camera locked up after shooting a few shots in succession. I switched to a Lexar 400X card and all was well again. This very nice camera seems to have champagne tastes and it balks at average speed cards. Not a complaint, just an observation that may help someone like me.

The fact is that some 3rd party batteries are of low quality and thus risky to use. There are some that are likely made by the same companies that supply Canon since it is clear that Canon contracts out the supply they sell under the Canon name. What's wrong with using the oem batteries is that , contrary to your evaluation that they are not all that expensive, the 3rd party batteries are approximately a third of the oem price or less. With that in mind, identifying a reliable alternative to one that says Canon on it can represent a significant savings with little or no risk for those of us on a fixed income and lacking the luck to have won the lottery. That's why the question was asked and answered.