I don't, nor was I trying to.

My initial post said that the advantage to flying AC would be the better lounge at YYZ, and that the advantage to flying UA would be everything else. I suppose I thought that it was implied that "everything else" outweighs a visit to the MLL.

Comment about MLL vs UC was in response to the question: But then at E50K, you can use any *A lounge when flying on a *A flight, can't you?

Context, assumptions, etc. Anyway, I would never spend more for this trip just so I could visit the MLL. In fact, the AC price would have to be less than the UA price for me to take AC. Benefits of taking UA outweigh the benefits of taking AC (in this example).