Say my client is a hair stylist and is looking to bill clients right after doing someone's hair. Would I go the merchant account route or the online "Paypal" route for storing customer "profiles" and CC info?
For a hair stylist I don't see a need to go online and to keep the customers credit card information. So I would say go for the traditional merchant account and physical terminal.
Use a virtual terminal / payment gateway with a storage vault. The gateway stores the credit card information for you. You can later charge the card for a different or the same amount. You still need to be PCI compliant, but you aren't the one storing the card so the PCI complexity is reduced a lot. There are payment gateways that you can hook a card swiper to and use them like a traditional credit card terminal.