No problem, really.
I haven't used O'BONs.O_o I'd love to try it out though I have to try it out if it is good for me or not.
But I recommend you try them out. There is no good or bad, it's how you use them. If you get used to one type of pencil, it's weird when you try to use the other. Kinda like how it feels like when you use wooden pencil when you are used to Mechanical pencil. ....or some thing like that.
Because 6B ~ 10B are so dark, it's kinda hard to tell when you are putting too much pressure on them. Same goes for 8H~10H they are super light, I can't tell the difference.
when you use pencils, grip loosely, and kinda slide through the paper, instead of pressing on the paper.
you can easily tell the difference when you rub them on your fingers and the wiping it off on the paper.
I love mechanical pencils, but the drawing ones (2.0 lead, I think.) are so expesive.. -.-.. $20+ each....
2H ~ 8B is a good start, actually. It's just that for me, 2H is still a little dark for me to use on some shades.
I sketch with F and HB (and for some shades), as well as H if I want to skech something extra, like shading boundaries. Of course, B is for dark shadings and H is for light shadings.
I think sketching with H ruins the paper(if you sketch too much) and B is just too dark for sketching and it will leave marks even though you erased them.
but you don't have to listen to me since I didn't eve ntake art class yet. =-= wish I did.
This is just based on the experiences, try it and eventually you'll get it. ^^