Hello William,
S08P is the latest family of S08 devices. It is perfectly recommended for new designs. As well as Kinetis L family, which is completely launched and available now.
If S08PA fits your requirements, the price will be less than a Kinetis L family. It is your choice to keep your code/project in the 32 bits world (The future of MCU will follow this path) or to use a 8 bits MCU for the next few years.
And there is the new family, Kinetis E, which is pin to pin compatible with S08P, just in case you want to migrate in the future your design to 32 bits again.
Regards,
Santiago