Det is also itemized heavier so that you get less of it, roughly 66-70% of what you'd get if it were any other secondary stat. As such, if you really want to get down to brass tacks, crit is still the stat you want to have on all of your gear, as opposed to determination (1.33 * .67 = .89). The only time you'd want to take det over crit is when you're forced to choose between equal numbers of both, which almost never happens unless you're dealing with a disparity in ilvl (which is going to choose for you anyways since mainstat trumps all) or secondary stat (wherein you have to start looking at stuff other than crit and det).
As such, when given the option, go with the crit: you get more of it such that, even though it's valued for less on a point-for-point basis, you still get more out of it.
