Now to actually get a product that is honest and performs as it is described can sometimes be a bit of a rarity, but I can pleasantly say that OPI has gone and done it with their RapiDry top coat.
After completing my manicure and popping on a nice colour I sealed the affair off with a coat of this RapiDry, less than 15 seconds later I got the old "aren't you ready yet" I picked up my coat and out we went, normally top coats that promise quick drying have let me down by being patchy, drying well in some parts but leaving edges a little wet and then I go and ruin them with my impatience. However as I realised grabbing my coat, my nails were dry, as I sat in the car I gave a cautionary rub of the nail and found a satisfying squeak, the sign of fully dry polish. Ultra happy at that point.
One coat of this left my nails dried in less than 30 seconds, fully dry. And the glossy shine lasted for about 4 days before it started to chip at the edges. One coat is all you need to seal off your nails, protecting and extending your painted colour. Highly recommended.
When I'm in a hurry and don't have 30 minutes for my nails to dry properly I use OPI Rapid Dry top coat. I find it does a great job and I'm good to go in under 10 minutes.
Tips: It seems to apply with a different consistency to OPI's Start to Finish (which I normally use, but takes a bit longer to dry) so it lacks a bit of the gel like glossy look. I think it's a good idea to have them both!