tethered droid

[newgenesis]

I am looking for a way to determine if there is a difference in one droid over another as far as functionality goes for tethering to a desktop for use as a modem. What is the limiting factor? The processor? The internal antenna? The OS?

I currently have the now outdated Eris and am up for an upgrade but before I put down $150 - $250 for a new phone I want to make sure it is worth it for my main usage