Pinyin is the way to go, hands down. No if but and.
Reading books that has written before 1990 and earlier, inevitable, one has to deal with Wade-Giles 韦氏拼音 and Pinyin.
Such as personal name of 周学熙: Zhou Xuexi in pinyin and Chou Hsüeh-hsi in Wade-Giles
Before the current standard of pinyin, Wade-Giles was widely used. The spelling, as you can see the example above, is quite a struggle from pinyin. For me, of course, I prefer pinyin, hands down. I didn’t know pinyin until I started to use QQ and now WeChat = very recent, no more than ten years. But I am a fan of pinyin. Because it is the standard, forward.
1990 is NOT a definite watershed. But since then, more and more books have began using pinyin. And now, it is singularly pinyin. I agree: more young people growing up without have knowledge of Wade-Giles. Why not make reading easily, by using pinyin?
I’m pretty surprised to find the monumental work by Ben Elman, published in 2000. I asked him why, he replied by saying simply, out of habit. hmmmm… It’s rather costly because as I read it, I struggle with Wade-Giles. On the other hand, another monumental work by French writer Alain Peyrefitte who used pinyin throughout his book published in 1992 – well done.