Mint is fine if speed is an issue, its one of the better choices. It's derived from Ubuntu which is a better choice for newcomers to Linux.
Linux is Linux and distros are a matter of taste really, at its core, it will perform the same.
The difference will be the GUI of course and how you get your packages but other than that, its so customisable that you can run other GUI's and package installers on other distros anyways...
But.... I personally think that the added complexity of Linux will bite you in the a$$ when you are going to need to meet a deadline or simply wont work when it's just not the time(eg. with a client).
Linux works marvelously when it's running fine, but when you start having problems, be prepared to spend hours and days on forums, typing terminal commands, trying to get that older version driver not to break dependencies...
IMHO, Linux is the better choice for setup and forget applications. You need a server, Linux. You need a hardware firewall, Linux and the list goes on and on...
But for a work desktop, where you need com ports, Ethernet and USB working with different obscure drivers.... You are going top spend LOTS of time on the terminal screen and probably will never get it to work properly at some point.
If your laptop is slow, I suggest you start by replacing your hard drive with a solid state drive (SSD) , then max that ram out with the fastest ram it can accommodate.
If your laptop is slow, it is probably because it has low ram and running VM's will make it slow no matter what OS you are running.
Low ram means swapping will occur and if you are not on an SSD, things will cripple and time out.
If you are running VM's you will need a minimum of 8 gigs of ram if you want to keep decent speeds.
The minutes lost waiting in windows because your laptop is slow will not compare to the hours and days lost trying to make Linux work.
IMHO if you want to start playing around Linux, install it at home and use it as your desktop.
Or you could keep Windows and install distro's you want to test out as VM's.
But if you really want to go for a Linux ride install Linux as your main OS, and run different Linux VM's to test out.
But testing out Linux on your work computer is not a wise decision IMHO.
Oh, and if you find windows resource hungry, start by disabling aero themes. Then you can search the web, there are tons of sites that explains how to disable services that eat up RAM and CPU time.