I would stick with Conti's based on your statement for a few reasons. They are a good bang for the buck, they tend to last longer that other tubes, they have a good puncture resistance and they use butyl tubes so you don't have to pump them up all the time.

For racing the Veloflex's can't be beat but the OP is using these more for training. I wouldn't train on $125 tires and they don't get nearly as many miles.