I admit I don't really know how to do stars for a place that (almost) exclusively sells olive oil and vinegar... I have nothing to compare.
Well, the owner is extremely friendly and inviting - happy to share her knowledge - the oil selections are thoughtful and unique and while I'm not some sort of oil or vinegar expert I have every reason to believe it's top notch quality. They even have butter and bacon flavored olive oils, and a caramel flavored balsamic vinegar... MMMMM!
I'm going to say 5 stars because for this kind of business I just don't know how they could be better, except maybe selling bread and coffee on premises..
Edit: There are apparently 2 yelp listings for this place, I think because they recently moved. It's definitely here on Baseline, at the address on this Yelp page.