Depends where you're located. Where I am, block would be much cheaper--provided you can find blocklayers.

I've built foundations both ways. But the lack of labour and the greater speed of pouring has tilted me permanently to poured. (Though I'm always open to change!)

I have both. I have a retaining wall with concrete that has been raked. It looks nice, does the job, and cost way less than my block wall. The block wall is in view of everyone who drives up and I wanted it to look natural.

We used Rosetta Stone and they were expensive... crazy expensive. I saved money by installing them myself but I have to tell you I called in every favor and had access to some pretty impressive equipment. Said and done, I think the stone wall looks great and I pray it doesn't settle, sag, droop, fall over, etc... As for the concrete wall... I have absolutely no concern about it. It will outlive me, no doubt.