My main concern is reviews of Harbeth talk about "warmth" and possibly less revealing.
I think some of these impressions were formed maybe 10 years ago or earlier. The new'ish Harbeth models strike an excellent balance between warmth and details/revealing. I have a SHL5+ and I can assure you it's the most balanced speaker I've ever owned. The super tweeter will give you as much detail as you like but without ever getting bright or fatiguing. If you ask me, choosing Harbeth to go with your Hegel amp is a no-brainer. You will, however, have to invest in quality stands ... they make a huge difference for Harbeths.