Question: Are certain guns better for the sport than others?
Answer: Yes. Certain guns are more popular in various divisions because they are more ideally suited to the sport. This can be because they have less recoil due to being heavier, have better triggers from the factory (thus easier to be accurate) and other factory features like easier to operate safeties, magwells etc. The other thing to consider is the aftermarket support for that firearm. The more popular models will have many different holsters and other accessories available. You also will want spare parts for competition. Some models and brands are almost impossible to find spare parts for.
What I normally tell customers is that if you are have not yet purchased a firearm, then definitely try to seek out and get your hands on the more IPSC suited models. Maybe someone at the local club can let you handle the gun and try the trigger etc. If you already have a firearm that can be used for your division, try the sport first and see if you like it. If you fall in love with it, then you can look at purchasing a more ideal firearm. If you don't end up liking it, then you are not out any extra money.