My experience was the same as @tseeb last year. Last year was my first with MCP, so I can't speak directly to the first year. However, @segbrown, I believe that you also are correct. I remember that part of MCP's sales pitch in spring of 2013 was that, while Alta was the one of the original participants in the MCP, they had added Snowbird as an "Alta/Bird" ticket to the '13-'14 offering. I also seem to remember that, much as they just added a seventh resort "area" for the upcoming season, they had sweetened the offering for '13-'14 by expanding the participation from four areas to six.
At the risk of turning pedantic, and surely of a thread hijack, it was MCP's addition of Mammoth Mountain as one of those six that got my attention. It has been stated elsewhere that the MCP really becomes a worthwhile investment with attendance at a minimum of two different areas. It really is not a good substitute for a season ticket or even, in most cases, for a marketing deal at any individual resort. My days at Mammoth had dwindled over recent years from about 15 to about 8, barely making a season pass pay for itself. On the other hand, my days at Alta/Bird had expanded in the same time period to about 12. The MCP was a total no-brainer for me, and I dumped my Mammoth pass after being a passholder for 10+ years. Good timing, it turns out, as last year's horrible season and my life's other demands had me ski at Mammoth only 5 days last year.
So, back to a bit more apropos discussion for this thread. The standard combination Alta/Bird pass, while a really neat idea, is not really that practical for the average Little Cottonwood Canyon skier. There simply is so much to explore at either area that the $30 upcharge just does not make sense for an everyday pass. Scuttling from one area to the other is an activity mostly to allow you to brag that you did it. However, it does work if you are wanting to coordinate residing at one area and meeting someone at the other, much like last year's Utah Gathering led to. Many took the free lodge shuttle or UTA bus to do just that, but others thought it was more interesting to do the crossover on skis, myself included. The MCP's free first two days significantly alters the penciled out math, of course. And, the additional 50% off days are gravy on top, as they still are marginally cheaper than the best deals one can find for a single pass price at either Snowbird or the less expensive Alta. Also to be factored in is the flexibility of the MCP to allow one to decide not to ski on a given day, rather than be locked in to a pre-paid multi-day pass that must be used or lost. I took advantage of that last year when one March day at Snowbird dawned on a dreary, overcast day that promised not to melt the death cookies that had formed overnight. I spent a much needed recovery day in the Cliff Lodge's gym/spa with a friend. And, by all accounts, the death cookies did not melt.