I was quite shocked Altium design content library's do not even have common standard components like IRFZ44, IRF3205 Mosfets.
These are very common components !
The computer is made by man. Altium created by man. No libraries? You, too, man! Create libraries for yourself.
I am not new to electrical engineering and pcb design but I am transitioning over to solidworks PCB powered by Altium.
Simply pointing out problems I find as a beginner to the the software.
Altium Vault: https://www.altium.com/documentation/3.0/display/VAULT/Altium+Vault
Nowadays, several manufacturers already have libraries of their own components for downloading. Not only for Altium, but for various ECAD's software.
I work in the Expedition PCB program, I find some components on the Internet, but most I create myself. I think that this is not a problem if the program does not have its own component library, it is better to create your own proven library. Very pleased libraries from manufacturers such as: Texas Instruments, Samtec, Nicomatic, Kemet