In your opinion, what is the easiest semi-auto to maintain/clean?
Short answer: Browning Hi-Power, Sig P-22x series, and Beretta 92.
While I can disassemble a Glock with my eyes closed, I find a lot of my friends have trouble with holding it correctly (thumb on backstrap, fingers over the top of the slide) and pulling it back just far enough to engage the take-down lever without resetting the trigger safety. It is very ackward for a novice.
The usual response by some is that people should take the time for more training and become intimately familiar with their gun, but not everyone lives, eats, breathes, and sleeps guns. Just because I drive a lot doesn't mean I know how to take apart my car. Nor do I even like to change the oil, even though I
can do that myself.
The beauty of the Hi-Power and the Sigs is that the slide can be locked back in order to engage the take-down lever. They don't require much handstrength or dexterity, since the person does not have to counter-act the tension of the recoil spring while engaging the take-down lever.
The Berettas don't even require the slide to be pulled back -- just turn the lever 90 degrees and pull the slide off the frame.
All three guns can, if need be, disassembled using one hand. Glocks, 1911s, HKs, etc., cannot.
In addition to it's thin grip, this is one reason I recommend the Hi Power to new shooters with small hands. It doesn't hurt that the weight of the Hi-Power easily dampens the recoil of a 9mm, but that's another topic.