As long as your membership and premier status are valid and active, you are able to use any *G benefits from your UA card.
I use TK and I like it much better. United Club access is more lenient (MileagePlus members can't access the United Club when flying domestic but Miles & Smiles members can).
http://www.flyertalk.com/forum/unite...gold-card.htmland the qualification requirements are lower than UA.