Try the Avent sippy cups. They have sippy spouts to start out with that are softer. As they get older, they have the harder ones. My 9 month only has problems with holding the cup up not with getting the liquid out. Plus they are pretty easy to clean.
We liked the Gerber ones too. However, with a good throw or drop the spillproof valve falls out. So we prefer the Avent over the Gerber. Less clean up needed and they are dishwasher safe.
Hope this helps.