Harbeth SHL5 vs 40.1

I currently own the Harbeth SHL5's and I'm considering upgrading to there 40.1's but I'm wondering how significant the improvement is based on the bucks that these speakers cost. Anyone have experience with these speakers? My Amp is a Cary 120s tube through a Cary SLP05 preamp.
if i had the room for the 40.1 i would seriously consider them, otherwise i'll just stick to my SHL5s.The bigger harbeths definitely need room to breath, otherwise, the bass could be an issue.
My room is 21' x 15' with short 6-7 foot ceiling. The 40.1's work quite well, but my room is heavily treated. Your 19' x 17' with high ceilings should be fine, but I highly recommend adding some acoustical panels (GIK Acoustic 244 panels are inexpensive and effective).
Many like the Harbeth sound, some less so:

Considering the starter of this thread already owns the Harbeths, and is thinking about upgrading in there line, we can assume he is one of the many that likes them.
Well, I pulled the trigger on the 40.1's so I'll let you know how they sound compared to the SHL5's. I get to keep the SHL5's until the 40's arrive so this comparison should be interesting.