Overkill pretty much got it covered. The only thing I can add is the gun gets easier to take apart the more it's disassembled. The parts kinda loosen and it's not as hard. Yes, it's a little more involved than other pistols but it's a great gun and well worth the extra few minutes to get it apart and back together.
+1 ... it is not that the Mark pistols are difficult to field strip and reassemble. The real issue is that there are a couple of easy steps that are hard to explain in writing that most new owners miss. (I did, anyway.)
The most common issue in reassembling a Mark pistol is that before you re-insert the mainspring housing assembly (MHA) into the grip of the gun, you need to have the hammer all the way forward. Otherwise the MHA will de-insert itelf as you close it, which is maddening. For a Mark III, this means that you must insert an empty magazine, pull the trigger, and push the hammer with a Q tip or some other tool such that the hammer is all the way forward. Takes about a second, but if you don't do this the MHA will not close properly. This is explained in the manual but many new Mark users miss this step at first. I did.
The other common issue when reassembling a Mark comes right after you perform the above step and insert the MHA. Sometimes the MHA closes properly, but once the gun is fully assemble the action will not pull back all the way. This means that the hammer strut was not positioned properly when closing the MHA. The easiest way to avoid this is when you close the MHA have the barrel pointed in the air. I make it a practice to point the barrel in the air and give the muzzle a firm tap with a nylon mallet. Often you will hear a little "click" which is the hammer strut falling into the correct position. When you close the MHA, if the hammer strut is correctly positioned per above, you will feel spring tension on the MHA for the last little bit as you close it. This means that all is well.
The above tricks were my own little problems when I was first learning the Marks. No problem now, and they are great pistols. Actually you can field strip and clean a Mark faster than most other pistols.