A short history: Santa Barbara is the name given to the National Armory that built Spain's military weapons when it was privatized in 1960(?). CETME was the previous name, just like the rifle. Since that time they have been producing M98 type rifles/actions until around 1984. Due to lack of sales they stopped. Strict European gun laws can mostly be attributed to that. Although in large part their market goal was selling in the U.S.
Some people say they are investment cast. Not true, they are forged. From the time period they were produced I say this isn't likely at all (investment cast). However, they did not have the time spent finishing them out as nicely as other actions of the day. So, they are a little bit rough sometimes and rougher in some unusual cases.
I have a Santa Barbara Action that was engraved and think it is a pretty nice rifle. I slapped an Adams & Bennet barrel on it hoping it would fulfill my need for an accurate .308. While I like the action I think the barrel is the real problem with the mediocre accuracy it gives.
A lot of Santa Barbara actions were used by P.O. Ackley (which used very good barrels) and were pretty accurate rifles. A few upstart companies built 'factory-off-the-shelf' rifles such as Golden State Arms. Those were hit and miss as to accuracy. Mostly because of where/from whom they could source the barrels.
So, if you are looking at a Santa Barbara action to build on, the only thing really to beware of is how it's finished out. It may be a little rough when cycling. Otherwise, stick a good barrel on it and you'll probably be happy with the accuracy you get with it.
Most Parker-Hales used pretty good barrels. I've heard nothing but good about them except some of the last ones. From what I understand, they made their own barrels. The cool thing with them is if they couldn't source good steel they didn't make crap barrels out of bad steel. For the first few years right after WWII, materials were in pretty short supply. After that, good steel making material became pretty plentiful.