I am very happy with this product. It is a well designed bottle, doesn't take up much space (long and narrow) and the bottle is almost full. Some other suppliers send a big bottle with 50% air in it.
The price is very good, while the quality is the same as any other supplier. Honestly I haven't noticed positive and negative difference compare to other suppliers.
One more thing, if you do your own research on the Internet there are different dosage for different conditions, age and health objective to achieve. These can't possible fit to any bottle.
I noticed a huge difference from 1000mg a day (2 caps) compare to 500mg (1 capsule) a day. 1500mg (3 caps) did make a huge difference compare to 1000mg. For me it feels like the winning dosage is 1000mg a day, when I take 2 caps in the morning. (I am a 40+ male)
I am able to concentrate longer hours and more energetic. How much more? Let's say about 15-20% increase. I was able to work for 5 hours, now I can do 6 hours without long break or other or a tea or something.
So great product, let's hope iHerb can keep up with supplying it.