I prefer OSX.
It is based on BSD so has a unix command line.
Native telnet, ssh and tftp server.
The java is wrong for SDM. Java is wrong on windows too but it is easier to downgrade. (I dont use SDM anyway)
On catalyst switches they ***** about browser incmmpatabilities but after you accept it sems to work ok for monitoring.
I have windows installed too for the few utilities that aren't avaliable on OSX.
Some of those I can run with winebottler.
If i had to choose between those three i would take the ThinkPad. Those laptops have an excelent reputation on the market, and if you can customize it for the i7 processor and better memory you will have a good laptop. If you want you could install Ubuntu on your laptop, and you will not have problems with network services or virus, and Ubuntu can live with Windows normally, so you can have a dual boot setup.
I guess the question here is what would you lose with going to Mac, and is that acceptable? AFAIK they don't have a Visio for Mac out...so you'd have to run that in Parallels or something if you use it as much as I do.
With that said, go with whatever you're more comfortable with. Personally I use WIndows computers because that is what I'm always provided, and I've never gone out of my way to buy my own laptop for work. I use Linux and Mac exclusively at home, though - so I would be 100% for using Mac at work if I had the option.
I am fine with cli most of the time. But for certain devices, like Asa and smb gears, cli doesnot make sense for advanced config/troubleshoot or cli simply is not available and only works properly with ie.
I am a big fan of apple and I can run vm occasionally but feel awkwards if necessary everyday. The other thing is will USB to serial adapter work in Mac and did any of u use the mini USB console?