i got a pair of ones with swivels and without swivels, for comfort i think i prefer the ones without swivels (i attach them to swivels via a short bit of colecord, tied with a larks head knot, distance from handle to swivel is about 25mm) just because I use a pinch grip and the using the knobs with swivels inbuilt puts the swivel directly in my 'pinch', which doesn't feel quite right to me.
I'm still finding them very heavy, but having said that the wooden handles I was using before were even lighter and smaller than px3s. My old handles were amazing for iso+float throws as their very light weight made the head virtually unaffected by the movement of the handle.
I havn't decided which way I'm going to go yet, it's probably going to take me a week of fiddling around and comparing to decide if I like the new silicon handles or not...

would really like to see what the silicon handles would feel like in some smaller sizes (hinting to HOP...

)