Beolab 1's are very clinical and surprisingly bass light for their size.

The addition of a Beolab 2 makes all the difference.

Pentas will sound quite dull in comparison but averall I think Pentas are preferred (by me) .

I have not heard Beolab 9's

I have both 9s and 1s. The 9s are different and I would say better. But, the 1s are spectacular. I find the bass totally adequate for music. 

I have the lab 1's with the bl 2 and find them fantastic for music. Must admit I never tried them without the lab 2.

A bit too bright for me but you can play with settings to change this. They are also big but my wife really liked a pair.

Car and Driver recently made decisions like this very easy by saying something along the lines of...

Given the choice of Corvette Z06, Porsche 911 and Nissan GT-R, you win any way you choose.

Just replace the above with PentaLab, BeoLab 1 and BeoLab 9 😁

I have them in 2 different rooms. One set without BL2 in the smaller room - very adequate. Two pairs in the main room supported by  BL2. As I can juice up the volume, bass support by BL 2 is evident.  

I would miss the BL1, presence in room is just beautiful and strong. 

BL1 are a bit susceptible to poor music input but with WMA lossless their clarity and strength comes through. 

I have them in 2 different rooms. One set without BL2 in the smaller room - very adequate. Two pairs in the main room supported by  BL2. As I can juice up the volume, bass support by BL 2 is evident.  

I would miss the BL1, presence in room is just beautiful and strong. 

BL1 are a bit susceptible to poor music input but with WMA lossless their clarity and strength comes through. 

After ~10 years with BL8000 + BL2, I bought a 2nd hand set of BL1s last year and really, really like them.  I too was deciding between BL9 and BL1.  My wife hated the BL9, a taller speaker was desirable given the room layout and I found a pair that  were 1/4 the price of the BL9.  I did think the BL9s sounded a little better, but I never got to the point of a home audition (I would not say they are 3 - 4 times better).  

With a well recorded source, they are wonderful... so much better than the BL8000s (lots of detail and separation - I don't know if that's the right word, but when I listen to classical music it sounds more like individual instruments rather than the "blended" (but nice) sound of the BL8000s).  Yes, they are a little "bright" (sharp/clinical) at times, and there is some music that I've found I need to turn down the treble - however, these are generally recordings that are too bright to begin with.  Over the holidays, they did impress my "audiophile" neighbor who originally "sniffed" at my B&O, and pushed me to demonstrate them to him... for which I was happy to oblige and, in the end, he muttered something about "having never given B&O the proper respect".

I've gone back and forth with respect to whether they really need the BL2 for music (I only listen to music on this system).  Right now, I have my BL2 hooked up with the BL1 mostly because I have it.  I have gone a few months without it as well.  I don't know if I'd buy one if I didn't already own one.  The improvement is subtle and doesn't apply to all music (IMHO).

Bottom line:  I highly recommend them.  The folks at my local B&O shop said that when they were selling them, they got feedback that they sound better in a big room, and sometimes not so good in a small room.  My room is not very large (~12' x 15' octagonish), but it does have a very high ceiling (18') which also seemed to make my BL8000s sound better.

Stan

I would agree about the high ceilings. My 1s sound much better in a room with ceiling close to 20 feet high at it its highest than they did in a room with 9 foot ceilings.