I love both incline and decline and rarely do flat bench. If you do lot's of decline be sure to switch it up from straight bar to dumbells. This will help the stabalizer muscles to grow also. Heavy overhead crossover cables will also make the lower pec more dense..
To be honest I've always treated declines like a red headed step child. Then recently I got tired of the usual deal so I threw heavy db declines into the mix.
Man, my chest never got so sore in a long time! Now I incorporate it in every chest day and my lower pecs are liking it too.
You gotta mix it up and switch shit around to see what works for you.
personally, declines do not do anything for me. I stick to regular bench and mostly inclines. I get the 'cut' at the bottom of my chest by keeping my bf% low.
At my PT seminar, Dr. Jack Barnathan, was saying that there was a recent studying showing that decline bench had 5% more muscle fiber recrutement than flat bench. I know thats not a lot, but a bunch of people think decline is worthless. Not I!!!
Hi, I started doing declines about 8 weeks ago, have noticed improvement in both strength (overall) and appearance, especially the area of you chest right beneath your boobs, much firmer and stronger looking