I just picked this one up on Amazon. It was voted best by America’s Test Kitchen. I think it works great!
Braun MQ505 Multiquick Hand Blender, Black https://www.amazon.com/dp/B01EA5ZI2U/ref=cm_sw_r_cp_api_i_c4h3CbZFF0W5H
Just in case your goodwill blender doesn’t work out 🙂
An immersion blender, especially with a whisk attachment, is very effective with any powdered meal replacement, and also easy to clean and store. I've had several years use out of this one but there are less expensive ones too.
This is the America's Test Kitchen winner Braun Multiquick 5, it's about $65.
I picked up the Breville BSB510XL Control Grip Immersion Blender, Stainless Steel for $100 a few years ago. When I checked current prices, $150, seems too high.
I think there's a few braun models. I'm pretty sure I have this one for the past couple of years.
I don't think I've yet run into a situation where it didn't do what I was expecting.
If you are getting into this on a regular basis, invest in an inexpensive immersion ('stick') blender, I have this one. Three seconds with the whisk attachment is all it takes to homogenize a blender bottle shake, and the whisk cleans up very easily.
Life advice: don't settle for "good enough" when buying something you will use every day. This Braun one is better than good enough, but see also the many related products Amazon helpfully shows further down the page.
I'll let /u/axcho and others answer the nutrition questions. I can say that from my experience with SF and KF as well as other powders, the quickest and most effective mixing is with a stick blender with its whisk attachment. This Braun one lasts a long time.
For anything approaching 100% use, it is IMO more efficient to mix a 2-liter, 2000 calories pitcher each time. (For nostalgia this one was what Soylent distributed with kickstarter orders back in the beginning.)
Mix in the evening, in the morning pour off into glasses for home meals and blender bottles to take out to work. If you don't have access to a refrigerator at work, invest in a couple of insulated wide-mouth bottles. A pitcher will last 2-3 days in a fridge that cools to under 50F.
Good luck!
Deal link: Amazon
I bought a year ago based on the America's Test Kitchen review. That page has an annoying sign-up overlay but if you click "read more" you can read the whole review including the name of the winner (on amazon).