Guess it mainly depends on your carpentry skill.
I have always built mine since it is way cheaper and I could make them more sturdy than factory and size them the way I wanted. So, if you have even basic carpentry skills, I'd build and save money for something else. Many examples on DIY threads to see examples but also pretty easy to come up with design on your own.
One caveat... if it has to go in a room that requires very nice furniture grade stand, may need to buy depending on your carpentry skills.
'tis my experience anyway.