I love my B72! I do occasionally feel some sproingy-ness with it - like going over BIG tree roots that can sometimes be hard to avoid on the trails 'round here. I'm guessing it doesn't have quite the shock absorbency of the B67, but since that's not what you're looking for it might work for you. I haven't had any problems attaching a saddle bag(when I had one - now I have a cool bike trunk!) to my bike with it. It did also squeak there for a while but the sound isn't from the springs. Knot and BIAK's LBS/mechanic friend, both advised me to oil some part underneath and it hasn't been back. Like Knot mentioned, it does require a seat sandwich for micro-adjust seat posts.
Everything in moderation, including moderation.
2007 Rodriguez Adventure/B72
2009 Masi Soulville Mixte/B18
1997 Trek 820 Step-thru Xtracycle/B17