Little mistake... retail/oem builds of Professional can also be activated via KMS if proper gvlk key is installed. VL builds have the gvlk key pre-installed. In fact Professional is the only version that supports retail, oem & VL licensing together.
You can use either iso to install win7 pro. To activate via kms, you'll need to install a key manually with the non vl while with the vl, the key is automatically installed. Long and short, you can use either, you'll NOT be stuck.
The VL one has KMS key integrated; on the other hand the other one has retail 30 day trial key integrated.