My favorite speaker of all time was bought without a demo BUT it was based on much feedback that in one case included a common denominator (Magnepan 1.7) that we both had owned and which served as a reference point. The new speaker exceeded expectations.
Another case was based on one very enthusiastic professional review. That speaker I never learned to love.
So with the right type of feedback (and a return policy) I would not be fearful at all. Gone are the days of showrooms packed with speakers. Honestly, that isn't the proper way to evaluate a speaker anyway.