Firstly, FanClub, which is only available thru Employers or Credit Union etc, is a rough equivalent to Disney Club at WDW. You'll get 10% off resort stays and vacations packages as well as discounted tickets. Like Disney Club, you can use it on both Coasts.
Lowes Card is a frequent stayers card. Membership is free (better to ring than join on-line) and for first three stays at Loews hotel gets you free complimentary gift (Cookies and Milk is our fav but includes wine, fruit basket etc.), free newspaper (local, WSJ or USA today) and free class upgrade IF AVAILABLE (Standard->Bay->Deluxe->Suite) based on your original booking (Standard gets bay view etc). This is Blue Status.
After three, you can use the card to upgrade to a suite from any class for $35, rooms are guaranteed with 48 Hours or more notice etc. All Blue status perks apply. And so on...
Fanclub needs membership which is available thru selected groups but gets Disney Club-like discounts. AP is still the best form of overall (rooms, meals and souvenirs) discounts at Universal. Entertainment card is known to be the best room-only discount at Universal and also had Dining and Shopping discounts.
Lowes card does not offer hotel discounts as such but the possiblity for room upgrade for the price of the class below is essentially a discount on the upgraded room. Plus the little things (like Cookies and Milk) make all the difference!