HI, I latched onto a pair of Harbeth SHL5+ about a year ago and I'm quite happy with them.
I compared them with the 40.3 but they were way too big for my room and quite more expensive. Basically the differences are that the cabinets are 2Cu3 and 3Cu3 respectively and the 40.3 sports a bass driver whereas the SHL5+ utilizes a super tweeter. The bass driver does lower the frequency response slightly but not enough in my view to eliminate the need for a SubWoofer. I think any smaller than the SHL5+ your looking at a bookshelf speaker as opposed to a monitor. It really comes down to the area you need to cover. A well balanced pair of speakers especially in the mid-range frequency range. Highly recommended.
I compared them with the 40.3 but they were way too big for my room and quite more expensive. Basically the differences are that the cabinets are 2Cu3 and 3Cu3 respectively and the 40.3 sports a bass driver whereas the SHL5+ utilizes a super tweeter. The bass driver does lower the frequency response slightly but not enough in my view to eliminate the need for a SubWoofer. I think any smaller than the SHL5+ your looking at a bookshelf speaker as opposed to a monitor. It really comes down to the area you need to cover. A well balanced pair of speakers especially in the mid-range frequency range. Highly recommended.