I'm about to leave for BLC. How difficult a school would you rate it?

same here

Its easy except for warfighting exam you can write down and learn everything they teach you and still fail because you can't locate an answer in a 600pg pdf file

BLC is not hard at all. I'm sure by now you've realized this. It is all paying attention and using the skills you carry with you and have learned in the military. You'll be fine, you'll do great.

It's really easy going. Mostly classroom work in a relaxed environment. Nothing is really pushed down on you, and for the most part get plenty of time. Yes, if you pay attention, you'll be perfectly okay. I'd put the difficulty of it at a 3 out of 10, and to make honor's it isn't that hard. Just don't do what I did and blow it on the last test! Haha.

To add onto my earlier statement, not only do you need to be right with your PT, you need to be CORRECT with it as well. My soldier who is at BLC now, just let me know they are very strict on proper form, so if your form has been rather lax by Army standards, they will gig you for it, and potentially boot you from the school if you fail your PT test.

You, going as a Sergeant, should be just fine. Honestly, I would say the course would only really be difficult for brand new Specialists and Soldiers that just do not go to the field or lead Soldiers. Just don't go in cocky and you'll be good.

Participate and be in the game and you will do fine, lead were needed and follow/learn when it is time to do so. Have fun and go full tilt

I actually just graduated this morning. I had a small class but in my opinion it is an easy class as long as you exercise time management and put in some effort.

I'm at BLC now graduate tomorrow, the best way to prepare is to bring your military bearing. Conduct yourself like a NCO at all times, no complacency after/before class; SGL's (Small group leaders/instructors) are always watching. We march by the cadre billings on the way to DFAC and they have been in their building staring making sure we are doing the right thing, when 'noone' is looking..(because now we march ourselves).. integrity. We are being evaluated for our skills as future leaders in leadership positions. Demonstrate your bearing and the rest can be learned in class.
Try to prepare yourself by learning how to write a memorandum, award DA FORM 638, and Sworn statement. if you don't have verbal confidence, practice because you will have to conduct training on a warrior skill, and give a oral presentation.
Go there knowing the NCO creed/ army song / army creed / division song.
Know how to conduct PRT (per FM 7-22)

Come with your uniforms serviceable and EVERYTHING on your packing list. to the T.
Come with your ASU's pressed, clean, and awards ON. Shoes polished and serviceable.
Boot cleaning kit comes in handy aswell.

Let me know if you have any questions!

4/10 difficulty

You will be fine. You already know most of what they are going to teach you and things that you have done in the Army. Still pay attention and try to do your best. Brush up on your land navigation.