Doh! I don't know if my perception is skewed, but I've always had a hard time to see the difference myself (after having been overweight for something like 15-20 years, I suppose it's kind of... logical?).
There IS a difference. My old pants are very loose and I had to buy new clothes, my face is way leaner, my bra size has shrinked (not in cups thought), I can snap my regular, favourite belt on the 4th hole instead of the 1st or 2nd one, I have more energy than before and fly in the staircase instead of dragging myself

... but it is nevertheless hard to see myself as a slimmer person. It's also due, I think, to the fact that all my 'before' pictures were on a HDD that died last year, so I have absolutely nothing left to compare the 'now' to, except pics from high school if I find them again (I was about 160 lbs then I think).
But the results ARE noticeable. Other people just happen to notice them way before I do, because my mind is still too uses to the old me.

I'd say... people I hadn't seen in a few months noticed the first 10-12 lbs drop, in any case--although they may also have noticed it sooner if we had been around each other sooner. Before that, I don't know; it was probably more evident in the face and arms than anywhere else, but things may slim down very differently depending on the people.
If your stomach is your problem area, it may unfortunately be the last part where you'll lose.

I have the same problems with my thighs/buttocks (ugh, the horror, still), because it's where I gained the weight first and foremost; conversely, the puffy face was the first thing to go, as it was the very last place I gained. It WILL go eventually, just not as fast as one would wish. Unless someone can point me to a solution to make this happen; I sure would like to grab it fast in that case!
Hope this helped, even a little.