ps3 to 4. should I switch?

[Felis]

currently there is no way to change the license from ps4 to ps3. its a one way street

you can't downgrade, yes.
But you can buy a new PS3 box and use the registry key in it to register the PS3 platform to your account again.

Example
Before upgrade:
PC platform
PS3 platform

After upgrade:
PC platform
PS4 platform (the previous registered PS3)

Add PS3 from a new box again:
PC platform
PS4 platform
PS3 platform