Definitely gaining muscle. My arms used to be skinny as $hit, and I had no chest. Now I'm gettin pretty big for what I used to be. I mean along with all I've been eating and the shakes I'm sure my body fat % has gone up a bit as well, but not much.
As for the ab exercises. I've tried it all. I dont limit myself to a few exercises. Every day I switch it up and I do 3-4 different exercises per day for abs to work different parts (upper, lower, obliques, etc). What I've actually been trying lately is a lot of weighted stuff for abs. If I do leg raises, put a medicine ball or weight between my legs, or use one of those weighted ab crunch machines you always see at the gym. Believe me, my abs are rediculously strong, its just weird that they've NEVER changed appearance. My top two abs are really defined, the middle two are so-so, the bottom dont pop at all. I know the leg raises/flutter kicks are supposed to work lower a lot but it hasn't done jack for me.