Try the gels first, as they are strange when you first eat them..and you will need water to wash them down. Some nutrition stores that carry gels will allow you to sample some of the flavors and brands. Since you already like Clif, you may want to try Clif Shots. I use them and they're great. Word of caution...some have caffeine and some don't. I use the caffeine Sonic Strawberry. Make sure your stomach can handle caffeine during exercise. Most gels are 100 calories and have around 25g of carbs, 50mg of sodium, and 50mg of potassium. They are close to the same as what you will get with one of your Clif bars, except your stomach won't have to process a solid...like what Batman said.

Some people actually mix the gels with water in one of their water bottles, which you could try. It makes it easier to take while riding. Crashing trying to open a gel pack would not be a positive experience! Considering the date of your olym, I think you have enough time to try out some gels. I agree with Batman that gels are usually easier for your stomach to process; however, everyone is different and you should make sure they work for you BEFORE the race.

Just an example of why NOT to try new things during a race. I ran a 1/2 marathon a couple of years back and used gels. At one of the aid stations, a volunteer handed me a gel, which i put in my pocket with my other gels...dumb move. It was a mocca/coffee flavored gel and I ate it without even looking at it. STUPID. Seems very innocent, but I ended up with the worst stomach ache from it...and was miserable for the last 4-5 miles.