Back when I was a general member in 2004 I did the Maple Leaf thing.

It is certainly more economical than an actual RCC membership, but there are a few (relatively minor to the potential savings) downsides:

1) The exchange rate is not what it was a couple of years ago so it isn't as great of a deal as it once was.

2) Long processing times. Unless you spring for the expidited processing, it takes weeks to get your card. Also if you do go for expidited processing, you will also be charged for the overnight shipping of your card from canada on top of the expedite fee.

3) No access to USAir clubs.

4) Only one guest instead of the two allowed by RCC (although this is rarely enforced).

5) It takes a lot longer to check into the club with a MLL membership. At best they will need to swipe your ticket and enter youtr card number into the system. Quite frequently they will have trouble finding the screen to enter your number. Often they will need to look it up to confirm that you are entitled to access.

In one case at IAD I was outright accused of scamming in front of a traveling companion and many other RCC denizens waiting for entry. I was made to sit until the line cleared, eventually granted entry only to have the matron chase me down and announce publicly that I really shouldn't have been allowed in after all. She also refused my request to get a service director. I was livid (and still am), but UA and MP were amazingly unsympathetic after the fact, but assured me that they will update their training procedures (apparently "Don't humiliate and harass customers" was not already covered).

Now that I am a 1K, I have gone for the RCC membership. Life is a lot easier.