I never actually had the MC, but the first guys I gamed with had one. I believe they had MC 1 along with the DL and FR MC pages. By the time I started getting the books myself, the MC was history and so I had the 2e MM instead. Also, the later appendices dropped the whole binder page format and were released as softcovers, and I have some of them as well.
Personally, I thought the basic idea itself was interesting. It allowed a DM to compile his own unique monster collection, and a DM only really needed to take out the pages he would use for a given adventure and not have to lug more books to the table. But as a DM who does keep campaign notes in binders, I'm well aware of the flaws. Durability is the biggest issue. Most of you guys mentioned that the pages ripped easily. TSR really messed up there, and didn't take into account that the setup would likely entail a lot of wear and tear. Also along the lines of durability is the binder itself. Binders have a tendancy to fall apart after a while, though I suppose a DM could just replace the binder with any old binder if he really needed to.
Also, if I'm not mistaken, the basic AD&D monsters were released in two seperate compendiums, MC 1 and MC 2. That seems really stupid! Why make a DM buy 2 products to get what he needs instead of making a single product. Oh that's right, I almost forgot. This was the Lorraine era at T$R.
Anyway, from what I've heard and read about people's experiences with the MC it seems to me that is was an interesting idea, but one that wasn't thought out thouroughly and thus executed badly. And like people stated above, the SRD can be easily used to make printouts of monster stats for 3e, and so the best aspect of the MC, the portability, can be used today by DMs who wish to do so.