Thanks for sharing Mike!! You pose a great yet surprisingly difficult-to-answer question. Here's my take on the subject:
Harbeth has certainly made it clear that they are no longer interested in making loudspeakers that adhere to the same old BBC character that has more or less remained unchanged for the past 40+ years. The SHL5+'s are, per Alans words, the first set of Harbeths that showcase what their Radial drivers are capable of. Suffice to say, the sound of these speakers is far more neutral and dynamic than their predecessors. Now, does this mean that they are embracing more of a "Hi-Fi" sound? Honestly, I think the answer is both 'yes' and 'no'. Here's why I say that...
At the end of the day, it all boils down to personal reference points.
If you're used to loudspeakers that are voiced aggressively throughout midrange and treble, ala, most Focal, Revel, Magico, Thiel, B&W, JBL, Klipsch, vintage Wilson Audio, etc..., then you'll probably walk away thinking that the SHL5+'s retain a very smooth and even-keeled character.
If however, you're used to your classic Spendors, vintage Harbeths, Sterlings, Rogers, Audio Notes, or just about anything that delivers a supremely colored (ie: rolled off and warm) presentation, then you may find the SHL5+'s to be surprisingly forward... bordering on aggressive.
When you get right down to it, I think Harbeth is trying to have their cake and eat it too with the SHL5+ speakers. Whether or not they achieve that goal boils down to personal preference and system setup. As I mentioned in my review, you gotta put in some work if you really want hear what these speakers are capable of. Once you get them dialed-in though, I think it's safe to say that there aren't too many music lovers out there who'd dislike em'.