I'm on Rotterdam to London now, in Eurostar Plus, and the food, such as it was (just a near-freezing temperature couscous salad for the vegetarian option, with a miniature Green & Black's chocolate bar), didn't come out until Lille. From Rotterdam to Brussels, nothing: no welcome from staff, no mention of when the "evening meal" (not that it's sufficient for a meal) would be arriving. And when it did arrive, there are "no hot drinks tonight at all", apparently. No coffees, no teas. It's just such a low standard of service compared to what it used to be, what it could be. Such a disappointing experience. This time it was "free" for me in the sense of spending Eurostar points on it, but on reflection it would have been better to keep the points and go on more trips in Standard and just bring nicer, better value, more substantial food (that i could eat when I like!) of my own.
From my experiences over the past few months, it's no longer worth paying for either Eurostar Plus (or Premier) unless you want a little bit more legroom, and less noise from other passengers. That's all it offers.