I already PM'ed Joe, but I thought I would chime in on here for others. I ordered a ferrule rod from him over the summer, but only recently used it on a shaft for a cue that was recently finished. Mind you I do not have a lot of table time in yet with the shaft (only a few hours... I haven't been able to play as much as I would like lately), so maybe I will revisit this post later with an update.
The white color is great in my opinion. It finishes and polishes up very nicely. For lack of a better way to describe it - it does NOT look cheap by any means and to me, is one of the better 'shades' of white I have seen. Not bright like white elforyn, not translucent like delrin, and no yellow at all. There is a picture floating around somewhere that shows the color difference with some typical ferrule types. I used it for a few hours and when I put it back in my case it looked like I never used the shaft - no chalk discoloration at all. I will keep an eye on this the more I use it to see if that changes. Personally this is not a big deal to me, but you have to admit ferrules do look nicer without bluing all over them
The feel is great and a noticeable change to me. Coming from the same shaft with same specs just a juma ferrule there is a difference. I will say though that rather than a Zan Medium tip (my choice for a while now) that I went with a Zan Soft with the Tomahawk. I kept reading about the firm hit and to be safe went with the soft tip to 'even out' the firmness I kept hearing about. So full disclosure, two shafts from the same maker and same specs, one with Juma/Zan Medium one with Tomahawk/ Zan Soft. I am sure I will end up putting a Medium on this shaft at some point. Ferrule is threaded, capped, and 1" long. I may try something a little shorter and uncapped down the road to see what happens.
For all of you on the fence about trying this material out - give it a try - you will not be disappointed. It is not going to feel bad, not going to sound bad, not going to look bad, and I'd be willing to bet you like it more than what you are using now if you give it a shot

I wish I had ordered a butt rod so the butt of this cue matched up with the ferrule and just because it really is a nice color of white.