I stuck some GG4 in my tank today and as far is I can tell it seems to do exactly what vision does. Brush glides better, bubbles on the windows when cleaning (although the bubbles with GG4 disappear quicker than vision which is much better when rinsing) and the glass is left with extra shine. Wether it aids cleaning is debatable, not really going to be able to tell until the summer.
Lee have you tried vision? A side by side comparison should show you why vision is better (in our opinion) than just something off the shelf like gg4. Would be interested to hear your thoughts.
Yes I have both.
What you may have is a mix of vision (what was left in your tank) and gg4. After a few weeks of just using gg4 the difference should be quite noticeable between gg4 and vision. Keep us posted. 
I haven't used vision for a couple of weeks, so I only had pure water in the tank. I was just interested to see what GG4 was like in comparison. I can't see myself using either long term as I don't really see any real benefit from them. I will try again in the spring/summer when snail trails/bee poo ect are baked on the windows more. As it is everything comes off the glass fine at them moment as everywhere is damp so everything comes off easily.
The summer will be a good test. I would definitely recommend using the full bottle of vision though and then make your mind up after. We are getting a lot of emails and messages that people are finding the most benefit on the second cleans as It gets better with time.
My dad said tonight he is flying with it. Due to the extra glide he is finding Leaded windows a real pleasure to clean same as me. I am DELIBERATELY not telling my dad about any plus points i am finding about Vision. So far i would say everything i have found to be a positive, so has he.
Will be ordering very very very soon 3 bottles is free postage is it not?
So, what else has dad said he's finding good about vision? Is it sheeting for him? Certainly not for me. In fact I've been doing 2nd cleans with it and noticed some weird findings on arrival. Good job it's winter and custy doesn't look out the window much this time of year.
Bungle not all glass will sheet. On most it helps, (majority of mine now show hydrophillic properties) but this is one of the lesser benefits. The main benefits are better cleaning power and leaving a good shine. This does become more apparent after about 6 months of use though.
Although some are saying the bubbles are slowing them done, we've found rinsing to be quicker with vision.
We didn't advertise vision as being a cure for hydrophobic windows so please don't expect that.
There is a way to make hydrophobic glass hydrophillic by using an additive though. This is something were working on, but won't be available for a while. There's lots more to come from us.