Europe produces a lot of high quality shooting products. That said, by the time they reach the US, import fees drive costs up making it difficult to compete with US made products.
When it comes to brass, IMO, Lapua is hands down the best. I really wish they made it in more cartridges because i will always buy it if I have the opportunity. It puzzles me why no US manufacturers have not risen to Lapua's quality.
As for rifles, IMO, most major US manufactures leave a lot to be desired in quality. They have a big corporation, bottomline/profit mentality and will produce the lowest quality product they can get away with with the best profit margin. I think Weatherby and Savage to a degree is an exception to this rule.
That said, there are smaller companies like Cooper who take pride in their work and produce high quality products for a reasonble price and then there is Dakota that produces higher end/priced quality prices. Also for the more serious and descriminating shooters, there is a large array of makers custom rifles and custom rifle components with an equally large array of fine gunsmiths to put them together. So although Europeans make fine rifles, there is a great deal of competion here in the US for probably a little better price.
Optics.... I currently own a Leica 1600 which is by far the best RF in its class. My next RF will likely be a Electronics Terrapin. Europe is way out in front when it comes to RF's. For rifle scopes, I think Nightforce is the best there is for a LR field scope. European glass has been better than the Japanese made NF glass until the development of the ACTAR and BEAST. Now I would say they are close to equal in glass quality. For the $$$$, NF is hard to beat in the US.
Powder... A lot of powder sold in the US is made overseas. Hogdon powders are made in Australia and are some of my favorite. When it comes to powder, I choose whatever works best in my rifle no matter where it's made.
Bullets... here, I think the US has the best selection. I find GSC bullets very interesting but also very spendy, so they need to prove their value to me to buy and use them.