What is thw difference between Balanced and Not Balanced versions?

In producing a Balanced Tension set, D'Addario has attempted to make the string tension of all six strings as equal as possible. The benefit to the play is that pressing on one string feels essentially the same as pressing on any other string. This is especially important for string-bending. Once you learn how much pressure is necessary to bend one string to increase the pitch 1/2 step (for example), the same pressure will increase the pitch 1/2 step on any other string.

Are these strings coated? The "XL" implies so...

NYXL strings are not coated, and XL is just a product series/family name, which does not imply any specific product specs. - Steve @ D'Addario

So what do you Blues players have to say about these strings?

Depends on the type of blues you play.... If you lean more toward "Delta", you probably wont like these much 'cause they give you more bottom end and highs and get rid of that muddy low-mid much sought-after in that style. Otherwise, many of us who pursue the more recent guitar gods (aka Hendrix, Stevie Ray, Page, etc.) will probably find these strings to be a nice "push" - to some, it will be like adding well-needed air to a deflating balloon.

Ya but does it djent?

My answer is yes. Great for metal and black metal. Not sure about math metal but I would stick with yes. Nita Strauss does solo work in heavy metal and only uses these strings. Same goes for me , and the many guitarists I play with. Used them in Vegas and received many compliments. To really enhance your sound your pedal board will need some adjustments.. You can also check https:/djenthub.com. Between my son, who has ten Solar guitars ,and my seven guitars, esp my Steve Vai blue floral jemm 77p and my Nita Strauss signature jiva 10 these are the only strings we use Good luck is your decision. Just keep in mind we all hear and feel things differently but so many of the musicians I play with all use these strings. Keep on rockin. And keep metal alive