Motor for arm: what should be used when?

[HarveyAce]

We are using two window motors in tandem to power the upper half or our arm. We were running into problems with them going really slow and not reaching past parallel with the ground, until we added a surgical tubing counterbalance . after that, we couldn't control it going down, because it went way too fast, and we put them on Victors instead of spikes and had to manually drop the voltage to make them go at a more controllable speed. any other solutions to this problem?

Also I was starting this thread to compile a list of what motors are good for what applications, and how to implement each in the applications. For example, one might say that FP's can be used for manipulators, but they are easily back driven, so explain how to use them without them back driving. Just a quick example. Hope this becomes a good resource for those that need a quick reference!