I like using Powershell cmdlets (where possible) rather than command-line utilities. It keeps the syntax consistent and often makes things easier in general.
But this is an exception. In most cases, if you want to create a Windows service based on a .Net assembly, I recommend that you use InstallUtil.exe, not New-Service.
InstallUtil uses reflection to find installers for the service, so the developer can put that information right into the .Net solution. This includes specification of the service name, display name, and description. When you use New-Service you have to specify these properties, and then ensure that you take any other special steps to install the service.
Both ways offer convenience, but using InstallUtil you can get consistency across all your development, test, and production environments without having to know anything but the assembly name.