The Madcatz streetfighter pads were really quite good in terms of being responsive and accurate, but suffered from being incredibly flimsy and overpriced for what you got. I do have a Madcatz arcade stick from the same era somewhere though, and that's really quite well made, again if overpriced (but that's the way of things with arcade sticks these days - I miss the days of the ASCII-made DC arcade stick, which I bought for half the price of a standard controller).
I think my favourite third party pad is a HORI FPS pad. The layout is fixed - with both sticks at the top which is a little weird, but everything else on it is configurable, from the springiness to the length of the sticks. It cost more than a standard pad, but it's so much better made that IMO it's worth it. I always buy HORI if I can.