First off, the main difference between gel polish and regular polish is that it lasts a whole heck of a lot longer. I use really strong cleaning products at my job all day, and the gels stay mostly in-tact up until I left for college. Now, granted, I only worked for a few days in between my mani and move-in, but I was still impressed with it's durability.
Secondly, the gels feel different. Something about the hardness of the polish or the smoothness of it--I'm not sure. They feel so slick and wonderful! That also means that the gels are SUPER shiny. I always think my nails are really shiny after I get a professional manicure, but the gels are at least 10 times shinier than a regular polish.
If you don't know this already, the gel polish is painted on in intervals--one coat, then a few minutes with your hands under a UV light, then another coat, then more time under the light, and so on. This means that the polish is basically bonding itself onto your nail, so DON'T TRY TO TAKE GEL POLISH OFF ON YOUR OWN! You should go back to the salon and ask them to remove it--otherwise, you could destroy your nail. I've seen it done, ladies. Be careful.
One last perk to having gel nails is that they are dry before you walk out the door of the salon. After your last sesh under the UV light, you are good to stick your hand in that chock-full purse and grab your wallet to pay. It's crazy! So, I definitely recommend giving this special manicure a shot.