The way that the Daggerhashimoto algo is designed it doesn't really matter what software you use, you will most likely get the same speed. Basically from the original ethminer included in the Ethereum github package to the advanced Claymore ETH miner software the actual miner speed is identical. Its just the way they designed the algo from the ground up.

The only difference is that ethminer was extremely buggy, basically from what I recall all my R9 280X rigs crashed every single time there was a DAG change. When claymore was released it fixed that and it also was more stable. And it had more features such as Claymore remote monitoring and Dual mining capability.

So in general the updates are mostly for stability and features instead of actual speed ups for GPUs.