Or just get an American Express card (Platinum, ideally - no additional fees) and net access to the Centurion lounge and all Delta lounges (when flying Delta).
The Centurion lounge is second-to-none domestically, and the Delta lounges aren't half-bad when it comes to the free booze (some are self-serve - Jack Daniels, Grey Goose, etc.)
United's clubs are a joke comparatively.
And they haven't reduced the fee even while losing Continental lounges when it was bought by United.
For my money, the Citi AAdvantage Executive card is a better similar card, because it now gives you access to all AA and USAirways lounges. While you're right that in my experience the Delta lounges are better (the only amex lounge I've been to is at mccarran), what matters most to me is a lounge in the cities i connect thru.
The Citi card is the same AF as the Amex Plat but Plat has policy of never waiving first year AF and Citi often has a promotion doing just that (or a portion of).