I buy the individual hardcovers, from my perspective there's no other choice. With books like Tintin & Asterix each panel is already very small so it's crucial to the enjoyment of the book to get the artwork in it's original size, I just can't imagine how tiny everything would be in the digest editions. Things like Dark Horse StarWars I can comfortably read in digest but not Tintin, no way!.
Even worse is the gorgeous complete adventures of Tintin box set is also in a digest format, I'd have bought that in a heartbeat but no they had to go and ruin in didn't they.