The beverage featured above is very similar if not identical to a drink I reviewed earlier by Haitai under the name "Ume Plum".
This drink was almost sickly sweet and not possible to consume in one sitting. It is a much larger quantity than the Haitai brand version and also seems to be sweeter and more artificial/brewed tasting. As the Haitai version reviewed earlier comes in a small can the drink seems a lot more enjoyable as you savour each sip knowing the next might be your last.
Having said that, I did enjoy this drink and it had a much more potent flavour than the aforementioned. During cherry blossom season in Japan, a fermented version of Ume plum wine is very popular, and having been in Japan during the celebrations a couple of years ago I can tell you that it's good stuff. This beverage reminded me much more of the wine than the Haitai version, so each has it's niche market I suppose.
In order to enjoy this beverage to it's maximum, I suggest consuming it at as colder temperature as possible.