I had listened to the Summit on many occasions, so I was not choosing blindly. I chose the Spire because:
- I am very sensitive to the panel / woofer transition "glitch". The Spire's crossover is based on the CLX technology, which is superb, IMO.
- I was influenced by Ken Kessler's review in Hifi News. According to Kessler, who lived with the Summits every day for 4 or 5 years - and loved them every night, the Spire was a hands down better speaker. In addition to the crossover improvement, he also mentioned that despite the bass specs, the Spires sounded "heavier" to him.
None of this, of course, invalidates the reasons Summit owners provide.
Ownership bias is definitely present for both sides - people just like what they own. Thus it is better to listen to both speakers to decide.