A good top coat is an important part of the manicure process (something which I have learned from Beauty Review) and OPI RapiDry will fix your polish in place and protect it from daily wear and tear.
The formula is pretty good, although I have noticed it does get a bit gluggy over time. It is easily applied, dries quick and has a glossy finish.
I am convinced there is probably a better top coat out there somewhere but for now this does a pretty good job.
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!