My copy of Captured Me 109s (their first book) quickly fell apart but they have steadily improved things since then and the this book looks like it will hold together quite well. A little thinner than their other books.
Yes they are expensive but they may be costly to produce with the amount of artwork that goes into them and they may not sell in large volumes.
The section on the Soviet Union includes a good number of wrecks rather than captured machines. There are small sections on Yugoslavia, South Africa, Czechoslovakia, South Africa, Rumania and Hungary. More interesting are the chapters on Fw 190 flown by Spanish volunteer pilots, Turkish Air Force and French built 190s. It ends with aircraft interned in Sweden and a section of supplements to Vol 1.