I'm an ex-pat Brit, living in central FL and I've been to the Daytona 24 Hrs twice, since I've been here. The facility is fantastic and a million times more fan friendly than Le Mans, but it is not a particularly good enduro circuit, from a purists point of view - being designed as a NASCAR superspeedway, the infield road course is a bit of an afterthought. This year saw the introduction of the Daytona Prototype (Fabcar) formula powered by a mixture of Porsche, Chevy and Ford motors - and there was obviously a lot of developing still to be done (they're getting there now, however). There was - and is always a large and varied grid and all of the cars are very fast on the banked section of the course. Weather is usually great (a bit chilly at night) and the crowd is small - about 75K at a circuit which seats 250,000 for the Daytona 500 - so you've plenty of room to wander about with no restricted viewing.
Air fares from UK are cheap at that time of year - and I'd recommend it for a relaxed, no hassle and very good race weekend.
That said, if you are into really classic races, wait until early March and do the 12 Hours of Sebring, which is a belter or get saving and come over for the Petit Le Mans at Road Atlanta in October. A mere sprint, by Le Grand Le Mans standards, the circuit is utterly brilliant and the race action intense. Probably the best endurance race in the world from a spectators perspective - and a proper end of season piss-up too.
I've only been here a couple of years - for a more informed opinion, seek out the views of Canada Phil, Pigeon, Fax and my brother Dave - they've all been doing these races for years.
Unfortunately, once you've experienced the North American offering, events in Europe (and Le Mans in particular) seem poor value in comparison.
Get over here - you won't regret it.