I don't have anything against synthetic fertilizers even though I do prefer organic when possible. But to me anything that gives you good results is just fine.
I put out lots of compost on the tomato beds which is great but by this time of year those tomato plants are taller than I am and they need the additional fertilizer. Of course with tomatoes one has to be careful not to give too much nitrogen or you end up with whopping size plants that don't bloom and set fruit. Not what one wants to accomplish.
