I will never buy from iBooks simply because it is a despicable store model which locks people into reading on iDevices only.
The fact that Apple is way too obsessed with fighting against the DeDRM tools is a factor too, granted. But it never even comes to that consideration, since i cannot possibly shop at iBooks without owning an iDevice.
Notice how Google Play offers options for those who don't have an Android. But
Apple doesn't want to sell me books they want to sell me iDevices. Their misplaced priorities mean that iBooks is not a serious way to get books regardless of the ease of use (
) or prices or quality of recommendations.
Frankly, the whole idea irritates the hell out of me to the point where even if I had an iDevice I still wouldn't use iBooks for that reason alone.