I'm still using the original bilberry formula from years ago ! I heard there was a change a couple of years ago and it wasn't as good ? I'm assuming it's back to its best now though! Which is good because I don't think my current supply will get me through summer !
The problem with Bilberry is that it's cheap, yeah, but it's just not the best out there (in my opinion).
If you use it in bulk you can dilute it down.. so you can mix it 1:1 when you need to but nevertheless... I've used loads and I'm really liking Chemical Guys Diablo at the moment.
The ONLY issue with it is one of consistency, due to it's gel-like consistency you need to find a good spray head that will work well with it.
Aside from that, really good, smells lovely and is safe for all wheel finishes (apparently. I've not tried it on bare ally yet).