There is a simple rule in dog training and that is that we don't get to choose what motivates our dog. Our dog chooses the motivation, and we need to work with that.
So if your dog doesn't care for hard discs when you start playing, start with a soft disc. If they like a particular brand or shape of disc, work with that until you get to a point where you can transition to another model.
Here are some of the competition standard and training discs available today and our thoughts on them regarding performance and safety.
When we're getting started playing disc with our dogs, it's entirely possible that we we'll use something other than a disc, such as a ball, if that is a high value motivator for our dog.
Once we have the dog interested in toys, biting, catching, carrying and releasing, we can then shift to a disc.
Let's take a look at the leading dog disc manufacturers and their discs.
Hero Disc USA is the American component of a Japanese company, Hero Disc. Hero Disc purchased some molds from Wham-O some time ago and has put together a line of discs that have become quite popular. They are working closely with the UFO

Based on an old Wham-O mold, Hero Disc 235s are light plastic and are a little bit over stable. 'They weigh in at about 109g.
I throw these discs quite frequently. I like them quite a bit.
The Hero Xtra 235 has made it very nice for people with hard mouthed dogs. Up 'til now, there had been no light plastic available for people with dogs that have steel traps for jaws. It was either waste a disc a throw, or throw heavy plastic. Hero has changed that with the Xtra. Weighing in at around 110g, the Xtra gives handlers with tough mouthed dogs the best of both worlds - the durability of heavy plastic with the performance of light plastic.
* there is a known issue with Xtras where they kind of deflate after a long period of time. The flight plate sinks into the rim, making for a distorted disc that winds up with a ring kind of feel. Not a big deal in my book, as they are great discs for tuff mouthed dogs.
The SuperHero, a durable heavy plastic disc, is based upon the 235 mold, but uses a heavy duty semi-opaque plastic. It weighs in at about 135g. Coming in multiple eye popping colors, SuperHeros are fixtures here at Pawsitive Vybe for their toughness, shape and flight properties.
* Heavy Plastic is heavy, and you should take additional care to ensure that you are not chucking heavy plastic at your dog.
Discovering the World is the main distributor of the Wham-O fastback, whcih has long been the standard disc for dog frisbee. Weighing in at about 109 grams, the fastback is a great disc for jamming with dogs. 
The fastback comes in several different blends of plastic - standard, flex, and Eurablend.
Flex discs perform extremely well in cold weather, and Eurablends are good for the tough mouthed dog.
Founded by former world championsPeter Bloeme and Jeff Perry, Hyperflite is the first dog specific disc manufacturer for Disc Dog competition standard discs.
A custom mold, the k10 is a smaller, more stable disc than the fastback or the 235. It has a stiff rim, a grip ring underneath and is quite easy to throw.
The k10 Jawz was the very first durable competition dog disc. It's extremely durable and comes in several semi-translucent colors.