I know there's a good amount of new DSLR shooters who haven't invested in ND filters yet, so here's a good example of the difference it can make to improve your DSLR video. To properly exposure on your DSLR you'll primarily be changing either Aperture or Shutter Speed. Since the majority of people love to shoot with a shallow depth of field (wide open aperture), changing the shutter speed is the only other option in bright days. This is where you could really compromise the video quality (unless you're going for that fast shutter look specifically). Get invested into some ND (neutral density) filters to cut down on the light so you can maintain that 'double framerate' rule.
To maintain the sharpest image possible, a single piece of ND glass is your best bet. The problem is that you need to have 1 filter for every sized lens, and you'll also need different densities according to the lighting. If you want to save time in swapping densities, you could get into Variable or Fader ND filters. These are adjustable filters that change densities as you rotate them giving you up to 9 stops in one single filter. Just be careful about the uber cheap ones. Here's a good article about those Variables http://cheesycam.com/variable-nd-filters-fader-filters/.
Here's a variable that i've been using with good results, but price has gone up a bit: http://cheesycam.com/nature-fader-nd-variable-neutral-density-filters/