I switched to sand more than a year ago because I have cory in all my tanks. It is so much easier to keep my tanks clean because all that poo and gunk don't fall down into the gravel. It just sits on top and I use a hose to just swirl around above the surface and the gunk goes right up the hose.
I used play sand from the hardware store (really inexpensive) and the stuff we get here looks like the bottom of a lake, so it's very natural. I got pool filter sand once because I thought I wanted perfectly white sand, but I found I didn't like the look as much. My 20g cory tank is all play sand and I like the look much better. One of these days I'm going to completely switch out the white sand in my 55g and replace with play sand.
One word of caution ... if you do use sand you need to rinse, rinse, rinse it, and then rinse it again before putting it in your tank to avoid cloudiness and damage to your filter. The LFS person who said it would clog your filter apparently attempted to start up the filter immediately after putting unwashed sand in the tank, and yep, that would clog it for sure.
If you do take the plunge and switch it out, it's best to put the fish in another container with their filter and heater until you've finished the process.