If you're on Facebook, there is a group call Blenderized Food For Tubies. They have a lot of good information and are very helpful.

I use a Vitamix and I also have a Blendtec. Both work great for blending food. I push mine through the tube with my syringe plunger and don't normally have any issues, however clogs are bound to happen. I've never had to get my tube replaced because of a clog though. See the Blenderized Food For Tubies folks (I think there's a yahoo group too) if you have trouble with clogs.