I have use flitz. It's slightly abrasive and it had rubbed quite a bit of the beadblasting on my CRKT KFF off. It's shinier than the new ones.
I think you're thinking of Flitz polish. Their wax is a different product.
I've never used Flitz was. I like their polish. But, for long-term protection I use and recommend Ren Wax. Every major museum in the world uses Ren Wax. If it's good enough for the White House, Buckingham Palace, and the Smithsonian, I guess it's good enough for my stuff too.
A lot of folks make the mistake of thinking that wax is only for collectibles. I wax any knife that I'm not going to look at for a few months. For example, I have a 2nd-rate fixed blade, it's a Kershaw, that I keep in my trunk for emergencies. It's got a bead-blasted finish. I look at this knife about once a year when I make my regular inspection. So, to protect it, I've Ren waxed it.
A lot of people are concerned about using a waxed knife for food. Well, the major ingredient in Ren Wax, the component that's left behind on the knife when the carrier evaporates, is high-quality carnuba (sp) wax. A lot of foods have carnuba wax on them. Most any candy that has a hard shell and a soft inside is coated with carnuba wax. The wax coating makes the outside shiny and seals the candy so that the soft center doesn't dry out. Carnuba wax has no real food value, but in small quantities it's quite harmless to eat.
I caution against applying Ren Wax to materials with a rough surface (some woods etc.) since it is difficult to get it properly buffed in the small nooks and cranies. The other place to be careful with it is where there's a very thin crack or space. For example, where in insert meets a bolster. If the knife isn't properly made, there'll be a thin crack there and, again, it's hard to buff all the excess wax out. It will slightly darken some leathers and unsealed woods. But, otherwise, it's good on just about everything.
A little bit goes a long way. The 65ml jar is easily enough for a hundred knives. One tip: don't wax one knife at a sitting if you can avoid it. It takes a lot of wax just to get the cloth you use "wet." So, if you start a cloth up, wax a few knives while you're at it. If you do this, about every forth or fifth knife will be free, i.e. you won't need to get any wax out of the jar.
This stuff is great for a lot of stuff other than knives. If you own anything that's silver, you know about tarnish. Ren Wax just stops it. So, if you have, for example, your great grandmother's silver candy dish that you display in your dining room hutch, you know that you have to polish it every three to six months even though you never use it. Polish it once, Ren Wax it, and you won't be polishing it again for years. And now you know why museums love this stuff.
If you own brass or copper, you also know about polishing. Again, Ren Wax it and you're done.
It's not abrasive, it brings out highlights in damascus and handle materials. It also keeps so called stainless knife steels from discoloring. 
