People That Have Upgraded From Harbeth 30.1s....

Many many years ago I was taken with the urge to upgrade from the speakers I was running at the time, B&W DM1800 (a remarkably good speaker in its day).  I settled on Thiel 2.3.  They were fine, but needed a good bit of power.  Unwisely, I availed myself of the store's trade-in trade-up program, to 3.6's.  By then, I had acquired a pair of Muse 175 monoblocks. Undoubtedly, the most "accurate" system I had assembled, but I just didn't want to listen any more.  I returned to the fold with ProAc Response 2.5's, a great speaker--better to my mind than many of their more recent offerings--and subsequently as they aged to PMC Twenty.24's, which I enjoy.  After another round of more exhaustive auditioning (that urge again), I'm pretty sure I'm headed towards 40.2's within the next year.  I've now heard a lot of makes and models, and to me--just me--nothing I've heard tops them.

Harbeth m30.2 + dual HSU ULS 15 MK2 subs. 30.2s are not an incremental improvement to the 30.1. Far bigger soundstage, greater delineation of voices, tighter bass. Overall more forward sound. With subs it is a very different speaker than the 30.1 - which I used with subs as well.  

I upgraded to jbl 4367

@prof 
Just wondering how long it may have taken you to get the Thiels placed in your room. From reviews it seems they are Very capable but finicky to placement, very narrow sweet spot and power hungry.  The 3.7s are on my short list along with Vandersteen 5A , Verity Parsifals and  Egg's Andra II.

jacksky,
It's completely the opposite:  The 3.7s are one of the easiest to place speakers I know of, their coax design with the special flat midrange (so so no coning around the tweeter allowing full dispersion) provides one of the widest sweet spots I've experienced with very little tonal balance changes, and I have found them easy to driver with 140W of tube power and even 14W of tube power sounded fantastic on them! 

The 3.7s sounded fantastic the moment I dropped them in to my room, and only got better as I played with position to conform to my own tastes.