When I first heard of Remy hair it was in a beauty supply. I thought that it wasn't the best quality and definitely didn't last long. That was years ago. Since then I've done my research, spoken to my vendor, and tried QUALITY Remy hair, all the thoughts I've had before are long gone.
(Link above is Remy C.B.K. Extensions)
To keep this VERY SIMPLE, the main difference between Remy and Virgin hair is the fact that you can not bleach Remy blonde. Yes Remy hair can be bleached but only to a #27 or a medium brown/bronze color. Virgin hair can be bleached to #613 or a platinum color. Some companies promote their hair as virgin and to easily tell if you really bought virgin hair, you can bleach it and see how light it gets.
Honestly though, that's about it. When I wear my C.B.K. Extensions, I'm always wearing Remy instead of Virgin unless I'm doing highlights or a style that includes blonde. I save some money with Remy hair and it last me a very long time with the right care. (Check out my blog post about proper hair care)
Again, I said I want to keep this simple for my ladies who don't know much about hair. Now there are other differences between the two like cuticles and processing but for someone who just wants to know is Remy hair worth it the answer is YES. If you want a natural brown color or black go with Remy. You're going to save money.
Both are very good choices and 100% human hair, it just depends on what you plan to do with the hair. Any other questions I can answer in the comments.