When embarking on a technology selection project, the natural inclination is to develop expansive requirements. This is OK as a starting point.
Remember, though, that you are not specifying out an actual implementation at this phase. You are trying to contrast potential suppliers and solutions. So while complete requirements are nice, prioritized requirements are gold.
Knowing which technical features and attributes are more important than others will make it easier to make rapid but effective decisions. It will also help you keep costs in line with your budget: excessive wish-lists lead to scope-creep, over-buying, and ultimately, budget-busting.
For more selection tips and hard-hitting evaluations designed to help you select the right technology, start by checking out a vendor evaluation from one of our seven coverage areas.