If you want to get a good chop cup without breaking the bank, Morrissey Chop Cups from Canada are a good value. They come in regular and mini sizes. They're also available in aluminum and copper. Good quality at an affordable price. For the money, they're real workhorses that will last a long time. I personally have a Morrissey mini copper cup that I bought 25 years ago, and it's still looks and works just like brand new. Scroll down to the 4th item on the page.http://www.morrisseymagic.com/morrissey_closeup1.htm
If you'd like to invest in some real quality, RNT2 offers many different style chop cups in different metals and finishes. These cups are generally a lot heavier, as well as more expensive. They are also the choice of many working pros. With these cups you have to purchase the chop balls separately, which RNT2 offers many different styles and sizes.http://www.rnt2.com/index.php?target=ca ... ory_id=184
As far as chop cups (or most other magic items for that matter) avoid the India stuff like the plaque! I'm sorry to say that most of the magic stuff that comes from there may be cheap in price, but the quality leaves much to be desired IMHO.
As for studies on the Chop Cup, the WGM Cop Cup DVD looks pretty good to me........must put that on my shopping list. Also, I understand that The Brad Burt DVD on the Chop Cup( http://www.penguinmagic.com/product.php?ID=S7695
) is excellent! I personally have not viewed this, but everyone I've spoken to that has, says nothing but good things about it. You may also want to check out Don Alan's work with the chop cup. too. Good stuff!
I hope that this gives you something to go on.