Here is my experience with B&O so far. Beolab 8000 on thier own are weak down low as you say but crisp and clear mid + Beolab 6000 we'll balanced at low volume bad at higher volumes. Beolab 8000 with beolab 2 are clear up top and good bass  but the mid power slightly off depending on volume range. Pentas - never experienced Beolab 1 very clear from mids + but don't have bass to match on their own. Beolab 1 + beolab 2. A completely different experience! I have never had my hair sand on end listening to music but these do it! Extremely clear and sound powerful and not loud. So maybe the penta MK3 would be good as they have a good reviews in comparison to the beolab 1 from what I have seen. Also depends on volumes you listen at i find these speakers sound very different depending on volume apart from beo1 + 2 which seems balanced all the way?Have to see what others say. There is also the style factor beolab 8000 look amazing when not in use penta not so sure. I need to try beolab 5 next and see if I can find some 90's on display. I will be interested to see what others say as the reviews I have seen are old now.      

My vote would always be Pentas from this choice. As most people on here know, I view the BL2 as an utter abomination that's only good for boom, bang, thump and exploding helicopter noises, and is utterly hopeless for music. IMHO, of course!

Ok, so I bought the Pentas MK3 refurbished in a BO store. Although they are ridiculously huge for my living room, they sound like heaven. Instantly put a smile on my face. Even better than Beolab 28, only a speaker of that volume can create such rich and full sounds. Mindblowing. Thanks for the advice.