Of the four you listed, I would only consider the first Stihl. You don't want anything that's old or beat up unless you have a backup, it could break down and leave you stranded. I started out with a Poulan Pro blower, which promptly broke down and forced me to buy a Husqvarna.
I would not buy a 4 stroke leaf blower. Too heavy. Only 4 stroke handheld I have is a Dolmar brush cutter, the 4 stroke torque comes in handy for cutting through thick brush and oak sprouts.
If I were you, I'd be checking out the new Husqvarnas. I have a 125B blower and I'm so impressed with it that I'm planning on getting all Husqvarna handhelds to replace the ones I have. I will warn you though, Husqvarnas come adjusted lean and have to be opened up to run right. I adjusted mine right out of the box.