Truthfully, a Warmblood is a type, really, a breed would be something like a Hannoverian, a Holsteiner, a Canadian Warmblood. However, let me give you some thoughts. The difference from a different breed to a Warmblood would depend on what you are used to riding. Generally, a warmblood would be a bit more laid back than your average TB, there are exceptions.
I can tell you about two that I have that have the same sire, a Holsteiner of the C line. One is lazy and kinda cranky, actually. She's a lovely mover, great jumper, but attitude problem. Some of it, bad training when she was young. Some of it, just who she is. Her sister, very dominant, very forward, very very bold. They aren't real spook machines, they are good travellers, like the new and exciting.
Various lines have specific traits that tend to run in them.
Well the one thing I was told when I bought my trakehner warmblood was to take his breaking and education slowly. It took my boy until he was 7 years old to mature physically and mentally to really get out of that 'baby' stage. But I'm not sure how old your new horse is so this might not be applicable to you.
As MagsNMe pointed out, a warmblood isnt a breed as such - its a type, so it does depend on the actual breed behind it as well as the sire and dam.
Lorenzo's sire was a real, scuse the language, b*stard - he was difficult, moody and stubborn (which is quite typical of Trakehners...so I keep getting told, but dont believe!) Lorenzo is a lovely boy who couldnt be more opposite in temperment.
Also, be prepared to hear the term "Dumbblood" a LOT from the warmblood haters :-/ They're just jealous :)
I always enjoy the folks that think, somehow, that you've taken the easy way out. Maggie is a holy terror. She's got siblings that are pussycats. Find the horse for you and to hell with breeding. I only ever really consider breeding when buying a young one, it helps you hedge your bets. I do have a soft spot for Holsteiners, big kids, good jumpers. Then again, I bred my Holsteiner/Selle Francaise to a German Riding Pony.