I've tried Autoglym, Megiuars and many ohters, but nothing touches the finish I get with the Zymol carnuba wax.
Yes it is expensive and cost about £80 quid for the starter kit, but I've had it 3 years and still on the first lot so it goes a long way.
The first time you use it be ready to put in some time as it's a 3 stage job, but when you come to put on more layers i can do my whole car in under an hour and when I get to the show I just spray on some glaze wipe it over a quick buff ad then spend the next three hours watching as other tried polishing there cars in the sun.
TOP TIP..... Now matter what wax you use try some Megiuars Clay it costs about £10 and will remove all the grime and dirt from you paint and make it feel like glass theres nothing else better.
Also remember that it best to use a wax not a polish like Autoglym the difference is Autoglym remove the old polish when applying a new cost where as with was you are building up layers of protection.
Hope this helps and isn't too boring