The 307 is actually my least favorite old type engine, BUT they are still good engines. The same engine builder friend of mine that I mentioned in the other post, convinced me (again) that they are good. After mentioning that they weren't my favorite, he then pointed out that they are the exact same engine as the 327 except they have a little smaller bore. Well he was right again. I bought my '72 C-10 Pick-up with a 307, 3-Speed when it had 95,000 original miles. That was just about 9 years ago and it now has 152,000. Still runs great.
The only thing I would say about it tho, is don't abused it and maintain it regularly. Changing the oil and filter often is very important.
Parts are no problem to find for any Small Block Chevy.