It doesn't matter how many rounds a semi auto has if you can't fire it immediately upon drawing. You will have to draw, remembering to push that safety down (on the Mak, the Glock doesn't have an external safety) and rack the slide. This is physically impossible with one hand, unless you want to trust a "belt rack" to that tiny rear sight on the Makarov, or the plastic rear sight on the Glock. A belt rack is using the rear sight to hook on the belt and then push the pistol down to rack the slide. Not the easiest thing to do under duress.
In my experience, generally, reloading a revolver is slower than a semi. That said, with a little practice, reloading a J-frame S&W with the Safariland Comp I speedloader drawn from the matching 'pouch' for it is as fast as reloading either of my semi autos. Any other make or model of speedloader or speed strip is a
lot slower, and/or not concealable. The only revolver loading system that is faster is full moon clips, which are for .45 ACP chambered revolvers, or other revolvers that have been modified for them.
This list of priorities for a defensive handgun was posted on another gun forum:
1. Reliability, 2. Reliability, 3. Reliability, and 4. Stopping Power.
While the Makarov and the Glock are very reliable pistols, in your instance the fact that they have to be carried disabled, (That is, not ready to fire immediately) reduces the reliability. The fact that you have to actuate the action to get it into Condition 0 [round in chamber, safety off] at a time when your motor skills (and cognitive functions) are going to be shot to hell from adrenaline dump makes getting it into action quickly and successfully less likely.
We've had people on this forum who live here in the US raise the question of whether carrying a round in the chamber is best, or whether to carry in Condition 3, like you are required to with a semi. The general response was "Why would you hamstring yourself like that?"
I found this article on Condition 3 carry very interesting:
https://tgace.com/2011/11/08/condition-1-carry-vs-the-israeli-method/
The 'only' pro of the 640, as you put it, is a very, very important one! Being able to just draw and fire without having to perform feats of prestidigitation that would make any magician proud is a HUGE advantage-and in personal defense, you need every advantage you can get!
My recommendation remains the S&W 640. (With a reload in a Comp I.) And again, I agree with susieqz, whichever option you go with, train with it, and keep training! I see guys at the range all the time forget to even take the safety off, and they aren't even under attack.