LGs tend to have some of the best signal, although Nokia tend to have the best. As for the Samsung itself, well, its not Bad. If you are REALLY concerned about signal, such as you are often in an area with weak signal the LG would be better. But it really depends on how much you are worried about signal, because in all honesty your not gonna see an amazing difference, just a slight difference in some areas.
A good example though is my wifes previouse LGs. We are both ATT, and she had way better signal then I did almost all the time. And I went through 3 phones, the Razr, A samsung A707, and now the Blackberry 8310. She pretty much always had better service then me fo rhte most part. Although now she switched over to the Palm Centro, and gets alright service.