I say both both as well. Although they may have different forms, they are still forms of Taekwondo. If you believe you can handle it, then by all means, go for it!!! Both styles have great things to offer, and you learning them at the same time might actually prevent you from getting used to "one way of doing things".
And while General Choi's "you can't ride two horses at one time" statement may be true, i believe he is speaking in terms of different arts. It would be a bit more difficult in my eyes to learn, parsay capoeira and Goju-ryu at the same time, because the way of movement is so different... (to each his own, of course). But in this case, I don't think there will be any problem.
Besides, you can always enroll in both, and if it seems to be too much to handle, you can always stop one right? No harm in that. I don't see any negative aspect of learning both.... try it and see for yourself. (you can check out my profile too!). :asian: