I just tried Jake (and Soylent-like products) for the first time and here are my impressions:
It tastes like water with flour
It is so bland
It is too much sweet
The "banana" taste is very unnatural, so is the smell
After every sip I have a terrible aftertaste of... I don't know... artificial sweetener?
I wasn't able to drink more than 1/2 of the drink. My wife had the same, negative impression.
Jake bar was very so-so too, but I forced myself to eat it.