Are all fertilizers the same?

[gmlm]

question: are all fertilizers within reason comparable. just as is a Green Eagle 18-20-2 and a Reed perrine seed starter fertilizer the same. or is lebanon the best out there...and thats why they are so expensive. i really want my properties to look good and dont mind paying for the best product but if they all have a prodiamine pre-emergence (.36) with a 19-0-5 fertilizer what makes them so difference in price. unless its that each fert has a different idea for time release.