The drop ins should be hundreds cheaper than a spray in. I went with a Rugged Liner bedliner. It has a very nice texture to it, things dont really slide around, and you wont slip and fall if its wet.
I wouldn't say drop ins are junk, not even a little bit, yes drop ins trap water under them, but if they are installed right they wont shift around as much and chances are it wont rust your bed out as quick as you think. Chances are you will pay the truck off before any damage will happen if any at all. It all depends how good the install is and what you use your truck for. and in 10 years when it does start to rub your paint raw then rip it out and spend money on a spray in..
For me, I just use it as a typical homeowner would. If you move a lot of brick or concrete then its worth the 600-800 bucks for a spray in Line-X, but for 150-200 bucks for a good drop in by a good installer is worth it..
if you want pics let me know..