I am quite happy with Pentax optics. Like I said earlier, I own the DCF ED 10x50. I also own several of the Pentax XW eyepieces for my scope.
I have had a Pentax 8x43 DCF SP. Great bin, though I sold it when I bought a Swarovski SLCNew 7x42B. It was no doubt that the Swarovski outperforms the Pentax in every respect. But then I am looking for a 10x50 as a complement. Yes, there is the SLCNew10x50B. But this glass is quite expensive and heavy...
Do you have any experience about the optical difference between Pentax SP and ED serie?