WG hasn't been out long enough to know really how well durability is. I know I can get around 10 or 12 weeks out of UPP and I wouldn't expect WG to be too much different. The surface is definitely slick. I would give the nod to UPP for being a little slicker than WG, but they are both very close.
BF is really old news as far as I'm concerned. It was hot stuff in the beginning when it first came out, but it disappointed a lot of people because it streaks alot and has a real serious problem with dust attraction. UPP came out right after BF did and really burried the competition. People online stopped talking about BF after that. You hardly ever see it brought up on boards like DC or Autopia anymore.
It doesn't surprise me at all that a Z forum talks about Zaino all the time. Zaino users are almost like members of a cult. Its rare to find car forums that don't pick one product and talk about it exclusively. Boards like this one are a little different because there are many more people who have tried many other products extensively. There are no sheep on Detail City that are just going to go out and buy the most talked about product. The reason for that is because there simply is no 'most talked about' product. They are all discussed here pretty equally. The sponsors have their own forums where their products are talked about more than others, but mostly you could say that we try and talk openly and objectively about any product that comes up. We know that there isn't a "best" product out there, so we embrace anybody who can give insight on something we haven't tried yet.
The point is that if you want to know what is the best for you then you really need to try things out. Just because everybody else with a 350Z likes Blackfire or Zaino doesn't mean that you have to. The 350Z that I take care of on a regular basis never gets anything other than UPP and Souveran on it. I've given the owner the option of Zaino, Blackfire, Wolfgang, Klasse, NXT, #20, you name it... he likes the way UPP and Souveran looks and doesn't want anything else. I know a lot of people like that. I don't push UPP or anything on my customers. What looks good to me might not be what they want. I keep a wide variety of products so that they have a choice. If they don't know what they want then I pick for them. Honestly, usually its AIO and UPP for them. I've never had one complaint in the two years that I've been offering that combination.
wned , I've got wolfy+ souveran on my bimmer and it looks great, as for UPP, I got it ordered and still waiting :kneel :kneel 
