There were some stability issues when the frontend switch to ckpool.  Since then, nonnakip has been doing a ton of work to see if there was anything that could be done to improve stabilization.  Since there were different frontends running, nonnakip wanted to give miners a way to see what they were mining on.  Eventually I think nearly everyone will be on the ckpool (CKP) frontend as it has advantages.  You may have noticed some weird things going on with the charts and duplicate entries as everything gets put in place.  

The difference you will notice immediately when switching to the new ckpool frontend is drastically lower reject rates and a higher reported hashrate.