Originally Posted by sour

I must be in the minority as I've purchased more bikes and frames without riding them first than bikes I've ridden.

First and foremost you must know your measurements and what fits. Online fit calculators can help. Different geometries, materials, construction methods, and other decisions during the build, can all affect rider's feel. Reviews help, but you have to remember that all are biased.

You won't be able to compare bike A to bike B, but if you are buying without riding first, there are typically other things that are more important to you than comparing feel.