Concierge level at places outside of WDW are very nice. Usually you have upgraded rooms/bedding and there is great food and a full bar with wait staff in a nice private area.
At WDW, not so much. It is nicer than regular rooms because you can get free water/snacks, but it's not at the level of service/amenities I've experienced at other resorts. The food offered is light snacks and there is no wait staff to serve you, no full bar (there is domestic beer and pretty bad wine).
Club level also provides the guests with concierge service. This will included little extras that you wouldn't have otherwise. One of the things at WDW is that if you have packages sent to your resort, they will be put in your room rather than having to pick them up yourself.