Contracts are changing library acquisition. It is a different world. If you come into it with your eyes and ears open and your focus firmly fixed on your patrons' needs, you will do fine. Come into it any other way and you are likely to be blindsided by the contract bus or worse, trampled by the herd of attorneys following the bus. Length is no indication of content.
Style is no indication of content.
The vendor's prominence gives no indication of content. Severe patron use restrictions. Responsibility to monitor patrons' use of works. No right to archive materials. Little or no documentation or help-desk access.